Which of the following is not a primary expression?

Which of the following can be both an input and an output device?

a. mouse b. keyboard c. monitor d. laser printer

If you need a function to get both the number of items and the cost per item from a user, which would be a good function declaration to use?

a. int,float getData(); b. int getData(float cost); c. void getData(int count, float cost); d. void getData(int& count, float& cost);