Look at this series: 100, 92, 85, 79, 74, _______.
What number should come next in this series?

​100, 92, 85, 79, 74, ____

Let's Check:

​Now, find the differences between consecutive terms:

100 − 92 = 8

92 − 85 = 7

85 − 79 = 6

79 − 74 = 5

So the pattern is: subtracting 8, 7, 6, 5...

Next should be: 74 - 4 = 70

So, the missing number is: 70

Thus, the correct option is: (a)