Can you explain why the answer is A and not D? It’s not a rule that Modulus can open only as a positive value. It can also open as negative. Is there any ETS rule that says Modulus will always yield a positive answer?
You are getting confused in the basics.
That holds true when you have an expression with a variable involve, inside the Modulus, which is equated to some number. So then you open the Modulus with the 2 different signs to get 2 different answers.
As for integers, the answer is directly just the positive number.
You can try to refer to this if it helps: Absolute Value of an Integer Definition, Examples | How to find the Absolute Value of an Integer? – CCSS Math Answers