A developer wants to set a variable to use a field from a Sendable Data...

To set a variable to use a field from a Sendable Data Extension in an AMPscript block, the following options can be used:

SET @firstName = %%First Name%% (B) - This syntax directly references the field value within AMPscript.

SET @firstName = AttributeValue('First Name') (C) - This function retrieves the value of the specified attribute (field) for the current subscriber context.