What does the sizeof operator return in C?

Answer: Option B

In C, the sizeof operator returns the size in bytes of the data type or variable provided as its operand. It is often used to determine the amount of memory occupied by a variable or data type.

Option A (Size of an array) is incorrect because sizeof returns the size of the data type or variable, not specifically for arrays.
Option C (Size of a pointer) is partially correct; sizeof can be used to determine the size of a pointer data type or a variable, but it is not limited to just pointers.
Option D (Size of a function) is incorrect because sizeof does not apply to functions in C.