Which of the following letter will replace the question mark (?) in the given series?
Y, T, P, M, K, ?

Correct option is D

Given: Y, T, P, M, K, ?
Now, find the differences between consecutive positions:
25−20=5
20−16=4
16−13=3
13−11=2
The differences are decreasing by 1 each time: 5, 4, 3, 2.
Following this pattern, the next difference should be 1.
So,
11−1=10, and the 10th letter of the alphabet is J.
Thus, the letter that replaces the question mark is J.
The correct answer is: (d) J.