Big Deal Alerts are a specialized, "out-of-the-box" notification feature specifically for the Opportunity object. This tool allows a Platform Administrator to define a threshold based on "Amount" and "Probability." When an opportunity is created or updated and meets these thresholds (in this case, >$250k and >75%), Salesforce automatically sends an email notification to a specified user or a list of stakeholders. This is the most efficient way to meet the requirement because it is a native feature designed exactly for high-value deal visibility. While Reports and Dashboards (Option C) can display this data, they are "pull" mechanisms that require leadership to actively check them, whereas a Big Deal Alert is a "push" mechanism that ensures immediate awareness. Guidance for Success (Option A) provides tips within a sales path, and Similar Opportunities (Option D) helps reps find related deals, but neither is designed for automated leadership notifications.

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A Master-Detail Relationship has several defining traits:5
Roll-up Summaries: This relationship is the only one that allows the Master record to summarize data (sum, count, min, max) from its Detail records (Option C).
Object Types: The Master can be either a standard object (like Account) or a custom object (Option D).
Ownership and Security: The Detail record inherits its owner from the Master record, and as such, there is no "Owner" field on the Detail record (Option E). Additionally, the detail record's security and sharing settings are inherited from the master, meaning permissions are not independent (negating Option B).
Option A is incorrect because an object can only have a maximum of two master-detail relationships.

Profiles in Salesforce serve as the foundation for what a user can "do" with records, specifically defining Object-Level Security (Create, Read, Edit, Delete permissions). The standard Marketing User profile typically does not include full "Edit" access to the Opportunity object by default, as marketing roles are traditionally focused on Leads and Campaigns. To fulfill the requirement of allowing marketers to maintain campaign relationships on Opportunities, the administrator must ensure the profile has the necessary object permissions. If the organization is using a custom profile based on the Marketing User template, the admin should edit the object permissions directly on that profile to include "Read" and "Edit" for Opportunities. This allows the marketers to view the records and update the "Primary Campaign Source" field. While a Permission Set could also grant this access, the question implies the admin is currently configuring the profile itself. Adjusting the profile's object permissions is the direct way to align the user's capabilities with the business's functional requirements.

The "Minimum Access - Salesforce" profile is a very restrictive standard profile designed to provide no access by default, adhering to the principle of least privilege. One of the specific permissions that is not included in this profile is the Lightning Experience User permission. Without this system permission, users will be defaulted to the Salesforce Classic interface (or potentially blocked from any UI if no other access is granted). To resolve this, the Platform Administrator should either edit the custom profile or, preferably, create a Permission Set that includes the "Lightning Experience User" checkbox and assign it to the affected users. This "unlocks" the modern Lightning interface for them. Options B and C relate to the design of specific pages, but they are irrelevant if the user isn't even allowed to enter the Lightning environment. Option A refers to a different feature set entirely and does not address basic UI access.