A program contains a void function named calcNewPrice. The function receives two double...

A program contains a void function named calcNewPrice. The function receives two double variables named oldPrice and newPrice. The function multiplies the contents of the oldPrice variable by 1.1 and then stores the result in the newPrice variable. Which of the following is the appropriate function prototype for this function?

a. void calcNewPrice(double, double);

b. void calcNewPrice(double &, double);

c. void calcNewPrice(double, double &);

d. void calcNewPrice(double &, double &);