Explanation
Marking stage dependent fields as required on the Opportunity page layout is a good solution to improve efficiency and data quality, as it ensures that users enter the necessary information for each stage of the sales process. Adding a Path component with fields and instructions aligning to stages on the Opportunity is another good solution to improve efficiency and collaboration, as it provides guidance and best practices for users to move the Opportunity along the sales cycle. Using two Tabs components to separate record information from activities may not be an optimal solution, as it may reduce the visibility and accessibility of important data. Setting up an approval process requiring manager consent at each stage of the Opportunity may not be a feasible solution, as it may introduce unnecessary delays and complexity in the sales process

Explanation
The two reasons that could be preventing this relationship conversion are that there are already two master-detail relationships on the Invoice Line Item and that Invoice Line Item records exist without having the Invoice lookup field populated. A custom object can have up to two master-detail relationships, so adding another one would exceed the limit. Also, a master-detail relationship requires that the detail records have a value in the master lookup field, so any records with a blank Invoice lookup field would prevent the conversion.

Explanation
Record-triggered flow is the automation tool that the app builder should use to best address all these requests of sending an email to the finance manager and creating a task for the sales manager when a new client is won.
According to the Salesforce documentation, "Record-triggered flows automate processes for you. They start when a record is created or updated, or when a platform event occurs." A record-triggered flow can perform actions such as sending an email alert or creating a record based on criteria or conditions. Screen flow, Apex, and Approval process are not automation tools that can handle all these requests.

Explanation
Apex. This is correct because Apex is a programming language that can perform complex logic and manipulate data in Salesforce. Apex can be used to create a trigger on the opportunity object that copies the value of the billing state from the related account record when the opportunity is created, and prevents it from being changed afterwards. The other options are not suitable for this requirement because they either cannot copy data from a related object (formula field, roll-up summary field) or cannot prevent data from being changed (workflow).

Explanation
One of the easiest ways to display real-time stock price for each account is to install a solution from the AppExchange, such as Stock Price Lightning Component3. This component can be added to any record page using the Lightning App Builder.