The correct syntax for passing all of the parent FlexCard's records to a child FlexCard is {Records}, which represents an array of records. The other options are incorrect because they either use an invalid syntax or refer to a single record instead of an array of records.

The best design is to combine a Loop Block with calculation-oriented actions. A Loop Block iterates over each item in a data array, allowing the actions inside the block to repeat for every element. A Set Values element inside the loop can set intermediate values, reshape nodes , or apply simple formulas per array item.
For more complex, multi-step calculation logic, an Expression Set Action is appropriate because it invokes a configured Expression Set and returns calculated results to the Integration Procedure. A Decision Matrix is mainly for table-driven decision lookups, not general multi-step per-item calculation. A List Action can merge or manipulate lists, but it does not perform the required calculation on every array element.

The correct configuration is to disable Save for Later through the OmniScript setup configuration, not by hiding it with CSS or deleting a nonexistent structural element. Save for Later is a framework-level OmniScript capability controlled by Save Options, so the proper approach is a configuration setting in the Setup tab. Conditional View is used for OmniScript elements, but Save for Later is not a normal element placed in the script structure. Custom CSS would only hide the button visually and would be a poor, fragile workaround. Salesforce documentation describes Save and Resume behavior as an OmniScript Save Options feature and confirms that Save for Later can be enabled or disabled through configuration rather than custom UI manipulation.

A FlexCard is the correct front-end component for a single, focused view on a Contact record page. The data may come from Salesforce and an external grant management system, and an Integration Procedure can be used behind the scenes to aggregate that data. However, the question asks which OmniStudio tool should retrieve and display the combined information in a compact record-page view. A Data Mapper Transform reshapes data but does not provide the visual record-page card. A Calculation Procedure performs calculation logic, not case-manager display. OmniScript is better for guided multi-step processes, not quick contextual viewing. Salesforce documentation confirms that FlexCards can be configured with data sources, including Salesforce or external databases, and can display contextual information on record pages.

The first responsible action is to validate the Data Mapper query design before committing to the implementation. Prefilling 15 user-based fields can be efficient, but only if the query is selective, returns only needed fields, and uses appropriate filters. Salesforce's Data Mapper best practices warn developers to avoid server performance problems and to ensure filtering and sorting operations use indexed fields where possible.
A Data Mapper Load is wrong because the requirement is to read current user data, not write data back to the User object. Converting the process to a FlexCard does not solve the prefill query risk. A Formula element cannot query Salesforce records. Therefore, option A is the correct risk-reduction step before development proceeds.