DOS 4. Select the best answer to each of the following: a.) Which of the following is the proper declaration of a pointer? A. int x; B. int &x; C. ptr x; D. int x; b.) Which of the following gives the value of the integer variable pointed to by a? A. *a; B. a; C. &a; D. address(a); c.) Which of the following gives the memory address of a variable pointed to by a? A. a; B. *a; C. &a; D. address(a): d.) Which of the following gives the memory address stored in a? A. a; B. val(a); C. *a; D. &a