Final answer:
The Current U.S President is the most likely not a variable, as it does not vary among individuals or across time in the same way characteristics like gender, intelligence, and religious affiliation can.
Step-by-step explanation:
The item that is most likely NOT a variable in a research context is c) Current U.S President. Variables typically refer to characteristics or properties that can vary among individuals or across time and/or space. Gender, intelligence, and religious affiliation are all aspects that can differ from one person to another and are considered variables in social science research. The current U.S. President, however, is a specific, non-varying entity at any given time and does not represent a range of values, therefore it is not a variable.