Afunction is executed when it is
a.
defined
b.
prototyped
c.
declared
d.
called

D. called

Explanation:

A function is executed when it is called.

Function definition comprises of the code body of the function.For example:

int add(int a, int b){

    return a+b;

}

Function declaration or function prototype specifies the signature of the function ( number and type of arguments, return type). e.g,

int add(int a,int b);

Function call is when the function is executed with actual arguments:

add(2,4);

This will return 6 upon execution of function body.

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