When future performance is expected to continue at the same cost efficiency (CPI), the formula to calculate Estimate at Completion (EAC) is:
EAC = BAC / CPI
Step 1:
CPI = EV / AC = 145 / 170 # 0.8529
Step 2:
EAC = 285 / 0.8529 # 334 person/day
Thus, the correct estimate at completion is approximately 334 person/day.
Option B is the original BAC and does not reflect cost inefficiency.
Options C and D are incorrect based on the formula and data provided.
References:
PMBOK Guide - Sixth Edition, Section 7.4: Control Costs
Earned Value Management Formula Sheet (PMI)
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The agile leader should develop working agreements with the team to address the trouble and disputes they are facing. Working agreements are a set of guidelines or norms that the team agrees to follow to improve their collaboration, communication, and performance. They help to establish a shared understanding of the team's values, expectations, and behaviors. They also help to resolve conflicts, clarify roles and responsibilities, and foster trust and respect among the team members. Developing working agreements with the team is a participatory and iterative process that involves the input and feedback of all team members. The agile leader should facilitate this process and ensure that the working agreements are aligned with the agile principles and practices. Escalating the issue to the team's manager (option A) is not a good option, as it may undermine the team's autonomy and empowerment. Removing some of the team members (option B) is also not a good option, as it may disrupt the team's dynamics and morale. Reviewing the roles and responsibilities document (option C) is a useful step, but it may not be sufficient or effective to address the root causes of the trouble and disputes. References:
* PMBOK Guide, 6th edition, page 52, section 2.4.2 Project Team
* [Agile Practice Guide], page 27, section 3.1.2 Working Agreements
* PMP Exam Prep, 10th edition, page 465, question 465, answer and explanation

In Agile project management, particularly Scrum, it is common to encounter situations where the team needs to conduct some research or spike to determine the best course of action for implementing a feature1. This is especially true when the team struggles to decide on the most efficient algorithm during sprint planning. Creating a new item in the sprint backlog allows the team to allocate time and resources specifically for this purpose, ensuring that the decision is made based on adequate information and development work2.
This approach aligns with the principles of iterative development and continuous improvement.
References:
PMI. (2017). A Guide to the Project Management Body of Knowledge (PMBOK Guide) - Sixth Edition.
PMI. (2015). Bring certainty in agile sprint planning through estimation2.
PMI. (2011). Agile project management with Scrum1.

This answer is based on the PMI Guide to Business Analysis, which is one of the reference materials for the PMI-PBA exam1, and the PMP Examination Content Outline, which is based on the Project Management Professional (PMP) objectives and content2. According to these sources, one of the key principles of agile project management is to empower the team to self-organize and self-manage their work, rather than assigning tasks or dictating solutions34. Empowering the team means giving them the authority, responsibility, and accountability to make their own decisions on how to perform the tasks, within the agreed- upon scope, quality, and schedule criteria34. Empowering the team also means providing them with the necessary resources, tools, information, and support to enable them to deliver value to the customer34. Empowering the team can promote collaboration, innovation, ownership, motivation, and satisfaction among the team members, as well as improve the quality and speed of the project outcomes34.
The other options are not correct because they do not foster empowerment and accountability among the team. Assigning the tasks individually based on the role of the team member may ensure expertise on the subject, but it may also create silos, dependencies, and bottlenecks in the team, and reduce the flexibility and adaptability of the team to changing customer needs34. Encouraging and assigning the team to perform demos of their products or software with the customers may increase the feedback and validation of the project deliverables, but it may not necessarily empower the team to make their own decisions on how to perform the tasks, especially if the functional manager or the project manager still controls the scope, quality, and schedule of the project34. Encouraging the team to keep the product owner involved when choosing ways to resolve the given task may enhance the alignment and communication between the team and the product owner, but it may also undermine the autonomy and creativity of the team, and create a dependency on the product owner for every decision34. References:
* PMP Examination Content Outline - January 2021
* The PMI Guide to Business Analysis
* Business Analysis for Practitioners: A Practice Guide
* Professional in Business Analysis Reference Materials

According to the PMBOK Guide, a context diagram is a visual representation of the product scope, showing a business system (process, equipment, computer system, etc.), and how people and other systems (actors) interact with it. A context diagram can help the project manager and the key stakeholder to understand the project's key performance indicators (KPIs) and how they relate to the project objectives, scope, and deliverables. A context diagram can also help to identify the sources of data for the KPIs, the frequency of measurement, and the reporting format. A context diagram can facilitate communication and collaboration between the project manager and the key stakeholder, and help to resolve any issues or disagreements regarding the project's KPIs. Autocratic decision making, expert judgment, and change control tools are not appropriate tools or techniques for this situation, as they do not address the root cause of the stakeholder's dissatisfaction with the project's KPIs, and may create more conflict or resistance. References: PMBOK Guide, Sixth Edition, pages 154-155, 176; PMI-PBA Guide, First Edition, pages 97-98, 102.