Answer :

Solution :

To find the missing group of letters in the given series, let's analyze the pattern in the given series:

Pattern: - The first letter of each group is increasing by 1 alphabetically (B, F, L). - The number of letters in each group is increasing by 1 (2, 3, 4). - The remaining letters in each group are in consecutive order (C, D, E; G, H, I, J, K; M, N, O, P, Q). Based on this pattern, we can deduce that the missing group of letters should start with the letter immediately after the last letter of the previous group (O) and have 5 letters.

Therefore, the missing group of letters is: TUVWX.