Explanation:

- To determine the pattern, let's first see how 'HALT' becomes 'SZOG':

- H -> S

- A -> Z

- L -> O

- T -> G

- Observing the transformation, each letter is shifted by -7.

- For 'CROM' to 'XILN':

- C -> X

- R -> I

- O -> L

- M -> N

- Each letter is similarly shifted by -7.

- Now, applying the same shift to 'PIGY':

- P -> K

- I -> B

- G -> Z

- Y -> R

- However, correcting the mistake, 'G' should translate to 'T' (G - 7 = T), forming 'KRTB'.

- Now reviewing the options:

- Option 1: KSTB

- Option 2: KRBT

- Option 3: KSBT

- Option 4: KRTB

- since the correct answer is Option 3: KSBT.