A symbol that modifies an action is known as

The correct answer is C. Interpreter.

A modifier is a symbol

that modifies an action. For example, in the expression $x^2$, the exponent 2 is a modifier that tells us to square the value of $x$. In the expression $x+y$, the plus sign is a modifier that tells us to add the values of $x$ and $y$ together.

A compiler is a program that translates a program written in a high-level language into a low-level language. A low-level language is a language that is closer to the machine code that the computer understands.

A mod is a modification

or alteration to something. For example, you might mod a car to make it faster or more stylish.

None of the other options are correct.