Answer:
pow.
Explanation:
Your answer is the second option or "pow". Pow, or power although is built into the language and is commonly used, it is not a part of the math library. Log, floor, and In are all common functions used in the math library. The math library is basically a collection of mathematic functions, you use these functions in order to solve more advanced equations which is why I would like to again empathize with the fact that although powers are used, they're not considered to be a part of the math library.
I hope this helps.