Using two separate Calculation Steps with the Conditional Step property selected allows the developer to specify different formulas based on different conditions. The ISTRUE(isCustomer) and NOT(ISTRUE (isCustomer)) functions are used to evaluate the Boolean variable in the Condition syntax. The other options are either missing the Conditional Step property, using incorrect comparison operators, or using an IF statement instead of separate Calculation Steps.

From the OmniStudio OmniScript Documentation:
* A Repeat Block (like BlkContacts) expects an array of objects.
* Each item in the array must contain fields that exactly match the UI elements inside the block.
* The parent JSON must include any top-level values used by individual input fields (like AccountName, AccountPhone).
Why the Other Options Are Incorrect:
* B. Uses Contacts instead of BlkContacts, and is incomplete/malformed.
* C. Repeats keys at the same level instead of using an array structure. This causes the data to overwrite and fail to display properly.
* D. Uses incorrect keys like " Name " and " Phone " instead of expected " ContactName " and " ContactPhone " , breaking field binding.
Reference:
Salesforce OmniStudio Developer Guide # OmniScript Repeat Blocks & Data JSON Structure DataRaptor Extract Output # Mapping JSON for OmniScripts

The Upsert Key checkbox indicates that the field is used as a key for upserting records. The Is Required for Upsert checkbox indicates that the field is mandatory for upserting records. The developer needs to check both checkboxes on the Account Id field to update the Account status only if the Account record already exists. Otherwise, a new account will be created.

Runtime OmniScript access alone is not always enough when the OmniScript executes Data Mappers, Integration Procedures, or Remote Actions that rely on Apex-backed services. Salesforce has OmniStudio security checks for Apex class access, and its documentation specifically describes configuring Apex class permission checkers so users require explicit access to the Apex class that administers a Remote Action. Save Options do not control Lightning component authorization. Multi-language settings affect labels and translations, not runtime component permissions. FlexCard permissions are not the most likely cause because the error occurs while launching an OmniScript and the scenario already confirms OmniScript runtime access.
The developer should therefore investigate missing Apex class access behind the OmniScript's actions.

Checking the Send Only Additional Input checkbox allows the Remote Action element to send only the key
/value pairs specified in Additional input to the Apex method. The Additional input should have the same keys as the method parameters, and the values should be set to {{InputData.node}} for each node. For example, AccountId: {{InputData.AccountId}} and ProductId: {{InputData.Details.Products}}.