Explanation:

Here’s what’s happening in this series:

- Letters in each cluster seem to follow a pattern based on their positions in the alphabet.

- Let’s break down each provided cluster:

- HSDA

- IZQT

- ?

- KNQF

- LUDY

- Looking at the first letter of each cluster:

- H (8), I (9), ?, K (11), L (12)

- So, the missing one is J (10)—the option you need must start with J.

- For the second letter:

- S (19), Z (26), ?, N (14), U (21)

- 19, 26, ?, 14, 21

- This sequence jumps by +7, then loops back to 14 and +7 again (26+7 cycles after Z(26), loops to A(1)). This suggests G (7) for the missing second letter.

- Third letter:

- D (4), Q (17), ?, Q (17), D (4)

- There’s symmetry: 4/17/ ? /17/4. The middle should be D (based on the symmetry).

- Fourth letter:

- A (1), T (20), ?, F (6), Y (25)

- The pattern alternates between advancing by +19, then -14, and so forth. Next logical step is M (13).

Now, options:

Option 1: JUEW

Option 2: JGDM

Option 3: JKDS

Option 4: JBCR

- Option 2, JGDM, fits the letter progression perfectly in context with the series.