It is C, but I’ll take the time to explain WHY it is C.
1/4 is 25% because 100/4 is 25. Thus, 40% is wrong.
1/2 is 50% because 100/2 is 50. Thus, 25% is wrong.
3/5 is 60% because 100/5 is 20 and 20 • 3 equals 60. Thus, 60% is correct.
6/8 is 75% because 100/8 is 12.5 and 12.5 • 6 equals 75. Thus, 68% is wrong.