From the given alternatives, select the number which can come in place of the question mark (?) in the following series: 12, 17, 23, 31, 42, ?

Correct option is B

12, 17, 23, 31, 42, ?
Let's examine the pattern in the differences between consecutive terms:
· 17−12=517 - 12 = 517−12=5
· 23−17=623 - 17 = 623−17=6
· 31−23=831 - 23 = 831−23=8
· 42−31=1142 - 31 = 1142−31=11
The differences are 5, 6, 8, 11. Observing the pattern:
· 6−5=16 - 5 = 16−5=1
· 8−6=28 - 6 = 28−6=2
· 11−8=311 - 8 = 311−8=3
The pattern in the differences is +1, +2, +3, so the next difference should be 11 + 4 = 15.
Thus, the missing number is: 42+15=5742 + 15 = 5742+15=57