ntroduction to Computer Science CSE 110 I 28. Which of the following function prototypes are valid? A. B. C. D. void doSomething(int& x, int y); void doSomething( int& x, int& y); void doSomethingl int x, int y); all are valid 29. You should make a parameter a reference parameter if: A. Always. B. You need to be able to use the value in a calculation, but not change it. C. You need the function to change the value of the argument passed to the function. D. If any of the other parameters are reference parameters 30. Which of the following is the correct way to close a file stream named outFile? A. outFile.close(); B. outFile.closeMyFile C. outFile.close("project.txt"); D. cout