In OmniStudio Integration Procedures, merge codes are used to reference data from the procedure's data JSON within element properties, such as an HTTP Action's URL. The syntax for these merge codes is %Node%. To access nested data within a JSON object, dot notation is used. The syntax %SetValues.Date% correctly references a Date node that exists within a SetValues JSON object at the root of the data tree. This is a common design pattern where the output of a step is namespaced under a parent node to prevent data conflicts.

A. t 'SetValues' ] [ 'Date' ]: This is not a valid merge code syntax in Salesforce or OmniStudio. It resembles incorrect JavaScript or JSON path notation.

B. {{SetValues.Date}}: This double curly brace syntax is used for data binding in other frameworks, such as Lightning Web Components or Handlebars.js, not for Integration Procedure merge fields.

D. %SetValues: Date%: The colon syntax (%ElementName:Node%) is used to reference the direct, unfiltered output of a specific element by its name. While a valid syntax, the dot notation is the standard for navigating the final, merged data JSON tree, which is the more common scenario implied by the question's structure.

1. Salesforce OmniStudio Developer Guide

"Access Data in the Data JSON". The guide specifies the use of merge fields with percent signs (%...%) to access data. It explicitly states

"To access a nested value

use dot notation." This supports the %ParentNode.ChildNode% structure. For example

to access a City node within an Address node

the syntax would be %Address.City%. This directly validates the structure used in option C.

2. Salesforce OmniStudio Developer Guide

"Integration Procedure Actions". In the section for the HTTP Action

the documentation shows examples of parameterizing the URL and other fields using merge codes. It reinforces that data from the JSON is accessed via the %...% syntax.