7. Let A = {(1, 22, 23, 24, 25, 26}. How many relations on A are both symmetric and reflexive? A. 215 B. 221 C. 230 D. 236 8. A = {1,3,5,7,9}, B = {2,4,6,8,10}. How many bijective functions can be formed from A - B to A? A. 0 B. 120 C. 1560 D. 3125 9. Which of the following is correct? A. (0, 1] = [0, 1]. B. Z-N is countable infinite. C. P(P()) is countable infinite. D. None of the above 3 10. R= {(a,b)/(a =b+1) V(b= a +1), a, b e Z}. Which of the following is true? A. R is symmetric but not antisymmetric. B. R is antisymmetric but not symmetric. C. R is neither symmetric nor antisymmetric. D. R is both symmetric and antisymmetric