Refer to the given series and find what should come in place of '?'. 163 132…

Step 1: Find the first differences between the consecutive terms:

163 - 132 = 31

132 - 107 = 25

107 - 88 = 19

88 - 75 = 13

Step 2: Find the second differences (difference of the differences):

31 - 25 = 6

25 - 19 = 6

19 - 13 = 6

Step 3: Since the differences are decreasing by exactly 6 each time, the next difference should be:

13 - 6 = 7

Step 4: Subtract this final difference (7) from the last term to find the missing number:

75 - 7 = 68

Final Answer: Option C