In Salesforce Flow, a Record ID, including a Record Type ID, is a 15 or 18-character alphanumeric string. The designated data type for storing a string of characters, letters, and numbers is the 'Text' variable. This is the most direct and efficient method for storing an ID for later reference and use within the flow's logic, such as in decision elements or record update actions.

A. Boolean variable: This variable type is incorrect as it can only store binary true or false values, not an alphanumeric ID string.

C. ID variable: This is incorrect because Flow Builder does not offer a distinct "ID" data type. Salesforce IDs are fundamentally strings and are handled using the 'Text' data type.

D. Record variable: This is incorrect for this specific requirement. A record variable stores a collection of field values for a single record, which is inefficient if the only requirement is to store the ID.

1. Salesforce Help Documentation

"Flow Resource: Variable": Under the "Data Type" section for creating a variable

the description for the 'Text' data type explicitly states: "A set of characters

letters

and numbers... This type is also used to store 15- and 18-character Salesforce IDs." This directly confirms that Text is the correct type for storing any Salesforce ID.

2. Salesforce Help Documentation

"Flow Data Types in Flow Builder": This document lists the available data types in Flow. It shows 'Text' as a primary data type for character strings and does not list a specific 'ID' type

reinforcing that IDs are managed as text.

3. Trailhead

"Flow Builder" Module

"Flow Concepts" Unit: This official training material explains the fundamental building blocks of flows. In its description of variables

it outlines that text variables are used for strings of characters

which aligns with the structure of a Salesforce ID.