Use a Record-Triggered Flow optimized for Actions and Related Records.
Submitting a record for approval is an action in Flow. Salesforce provides a Submit for Approval action, and after-save record-triggered flows are used when the automation needs to perform actions or work with related records after Salesforce saves the triggering record.
Option A is wrong because Fast Field Updates is the before-save path, mainly for updating fields on the triggering record. It is not the right optimization for submitting an approval request. Option B still requires a custom button and manual user action. Option C is unrelated because this requirement is based on an Opportunity record change, not a platform event.

When deploying from sandbox to production using Change Sets, the following are critical considerations:
A . Transactions will revert if the deployment errors - Salesforce applies deployments as a single transaction; any failure rolls back the deployment to maintain org integrity.
D . Change sets do not include all components and may require manual configuration - Certain components, such as record data or some metadata, may need manual setup or additional deployment steps.
Salesforce documentation emphasizes that change sets cannot deploy everything and must be carefully reviewed before validation. (Salesforce Help) B . Users being logged out is not required; deployments can occur while users are logged in.
C . Salesforce Connect does not automatically link environments; it is unrelated to change sets.

The correct answer is C. Unable to reference the child records.
A formula field on Account cannot directly pull data from multiple related Contact records because Contacts are child records of Account. Cross-object formulas work by referencing fields through supported parent relationships, not by traversing from a parent record down to multiple child records. Salesforce documentation describes cross-object formulas as formulas that reference fields on related objects, especially parent records through relationships.
Because an Account can have many Contacts, Salesforce does not expose that child relationship in the formula editor as a single field reference. For summarized child data, the app builder would normally use a roll-up-style solution where supported, or automation such as Flow.
A is unrelated unless the formula has already exceeded character limits.
B is misleading because the core issue is not simply that Account and Contact lack master-detail; it is that formulas cannot directly reference child records.
D is not supported by the scenario.

The correct answer is A. Two Master-detail relationships on a new custom object.
This is a classic many-to-many relationship requirement: one Contact can relate to many Solar Projects, and one Solar Project can relate to many Contacts. Salesforce recommends using a junction object for many-to-many relationships. A junction object is a custom object with two master-detail relationships.
The new custom junction object would sit between Contact and Solar Project, with one master-detail relationship to Contact and one master-detail relationship to Solar Project.
C could technically connect records using lookups, but the standard Salesforce data-modeling answer for a true many-to-many relationship is a junction object with two master-detail relationships.

The correct answer is D. Flow.
The requirement is to automatically clear the Phone field on Contact when the Do Not Call checkbox is checked. A record-triggered Flow can run when a Contact is created or updated, check whether Do_Not_Call is true, and then update the triggering Contact record by setting the Phone field to blank. Salesforce Flow supports updating records, including directly updating the record that triggered the flow.
B . Validation rule is incorrect because it can block a save but cannot delete or clear the Phone field automatically.
C . Quick action is manual, not automatic.
A . If-then rule is not the best current Salesforce automation tool for this requirement.