Answer: C. Function composition
Explanation:
If we have two functions, we can form a new function by composing one function into the other. Such functions are known as composite functions.
For example we have two functions f and g and produces a function h such that h(x) = g(f(x)).
It is generally a function that is written inside another function.
i.e. it is a process of using the output of one function as the input for another.
Thus, the correct option is C.
The required term: Function composition