Programmer-defined functions can be

The correct answer is C. either value-returning or void functions.

A programmer-defined function is a function that is created by the programmer. It can be either a value-returning function or a void function. A value-returning function returns a value to the calling function, while a void function does not return a value.

Here is an example of a value-returning function:

python
def add_numbers(x, y):
return x + y

This function takes two numbers as input and returns their sum.

Here is an example of a void function:

python
def print_message():
print("Hello, world!")

This function does not take any input and does not return a value. It simply prints the message “Hello, world!” to the console.

In conclusion, programmer-defined functions can be either value-returning or void functions.