A reason for passing a pointer to a function is

a$.$ to avoid the overhead of copying large data structures and to allow the called function to modify a variable accessible to the calling function are both true.

b$.$ none of these

c$.$ to allow the called function to modify a variable accessible to the calling function.

d$.$ to allow easy access to data in the function that is being called.

e$.$ to avoid the overhead of copying large data structures.