B. The output of one function is used as the input for another function.
Composing of function is a process in which output of one function becomes input of other function.
If we take two functions f(x) & g(x), then composition of this two functions be like : f(g(x)) ,where g is inner & f is outer function, i.e. g(x) is the input of f(x)
Also g(f(x)) ,where f is inner & g is outer function, i.e. f(x) is the input of g(x).
So from this description, we understand that ,the output of one function is used as the input for another function.
Learn more about composing functions here :
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