Explanation:

Let's break down the pattern in the given series:

- YXZ

- VUW

- SRT

- POQ

- ?

Let's look at each letter in the clusters:

- First letter: Y, V, S, P (decreasing by 3 each time)

- Y (25), V (22), S (19), P (16)

- Second letter: X, U, R, O (decreasing by 3 each time)

- X (24), U (21), R (18), O (15)

- Third letter: Z, W, T, Q (decreasing by 3 each time)

- Z (26), W (23), T (20), Q (17)

Continue the same pattern (subtract 3 from each letter):

- First: P(16) - 3 = M(13)

- Second: O(15) - 3 = L(12)

- Third: Q(17) - 3 = N(14)

So, the next cluster is: MLN

Let's check the options:

1. LMN

2. MLN

3. NML

4. LNM

The correct answer is Option 2: MLN.