Explanation:

Let’s solve it step by step:

- Observe MARKET (6 letters) is coded as 15.

- SUBMARINE (9 letters) is coded as 21.

- Let’s check if code = Number of letters × 2.5.

- MARKET: 6 × 2.5 = 15

- SUBMARINE: 9 × 2.5 = 22.5 (But coded as 21, doesn’t match exactly.)

- Try code = Number of letters + 9.

- MARKET: 6 + 9 = 15

- SUBMARINE: 9 + 12 = 21 (Since 9+12=21, maybe code = Number of letters + 12.)

- But 6+12=18 for MARKET, so this doesn’t match.

- Notice for both: The code may be Number of letters × (an odd number).

- Try more options...

- By pattern, the generally closest fit is

- 6?15, 9?21. The difference is 9?21 (diff=12), 6?15 (diff=9).

- The increment is +3 as number of letters increases by 3.

- For CONVENTIONAL (13 letters), add 3 to 12 (previous increment).

- So code = 13 + (12+3) = 13+15=28. Not in options.

- Looking at options:

- 1—31

- 2—24

- 3—27

- 4—23

- Try simple sum: 13+14=27 (number of letters + 14)

- Compare: 6+9=15; 9+12=21

- So pattern may be code = Number of letters + (number of letters +3)

- For CONVENTIONAL: 13+14=27

- So, Option 3 (27) is closest.

Correct Answer:

Option 3: 27

- MARKET (6 letters) ? 15

- SUBMARINE (9 letters) ? 21

- CONVENTIONAL (13 letters) ? 27