The required metric is the total monetary value of won Opportunities for each Account. Salesforce supports roll-up summary fields on Account that aggregate Opportunity Amount and apply filtering criteria so that only qualifying child records are included. The appropriate configuration therefore uses SUM on Opportunity Amount with a filter restricting the calculation to Opportunities whose Stage represents Closed Won. Option C would incorrectly include open and lost Opportunities. COUNT-based options calculate the number of records rather than total sales value, and the roll-up belongs on the Account because that is where the summarized result must appear. Salesforce ' s current documentation specifically gives the example of an Account roll-up displaying total Opportunity amount and filtering the aggregation to only won Opportunities.

Developer Pro satisfies both requirements. Salesforce ' s current sandbox reference states that a Developer Pro sandbox can be refreshed every one day and provides 1 GB of data storage by default, comfortably exceeding the required 250 MB. A standard Developer sandbox also has a one-day refresh interval, but its standard data- storage allocation is only 200 MB, so it does not satisfy the stated storage requirement without an additional storage upgrade. Partial Copy provides significantly more storage but can only be refreshed every five days. A Full sandbox mirrors production-scale data and storage but has a 29-day refresh interval. Therefore, Developer Pro is the only standard sandbox type among the choices that simultaneously supports at least 250 MB and daily refresh capability.

Page layouts are metadata components. When an updated layout is included in a deployment, the target organization receives the source version of that layout rather than merging independent layout customizations field by field. Consequently, if three fields existed only on the production version but were absent from the sandbox version being deployed, those field placements can disappear when the source layout configuration replaces the target configuration. Salesforce ' s deployment documentation emphasizes that metadata deployments apply the layout configuration supplied in the deployment payload and warns that page-layout metadata and assignments require complete deployment planning. Option A cannot be correct because a failed deployment is rolled back. Missing field permissions affect visibility, but the scenario specifically identifies fields disappearing from the deployed layout configuration. Therefore, B best explains the behavior.

The correct answer is C. Salesforce Schema Builder can create fields, including relationship fields, formula fields, and normal fields, and it also helps visualize existing object relationships. However, a field created in Schema Builder is not automatically added to the object's page layout. Salesforce documentation states that after using Schema Builder, the field must be added through the Page Layout Editor.
Why others are incorrect:
A is incorrect because Schema Builder can create formula fields.
B is incorrect because Schema Builder can create relationship fields.
D is incorrect because Schema Builder is specifically used to view and understand object relationships.

A custom field type change can substantially increase change-set deployment time because Salesforce may need to transform existing stored data to conform to the new field representation. Salesforce ' s official Change Sets Best Practices documentation specifically warns administrators to consider possible deployment delays when a change set includes custom field type changes. The documentation explains that these changes can require modifications across a large number of existing records and therefore can extend deployment for a significant period. Salesforce even recommends considering a manual field-type modification after deployment when avoiding the delay is important. Profiles may increase deployment complexity because they contain access metadata, but they are not the specific documented cause identified here. Dependent fields and roles likewise do not inherently produce the extended data-conversion processing associated with changing a field ' s underlying data type.