2E2, 1H9, 1K6, 1N3, ?

Concept: In this alphanumeric series, each term has the form digit-Letter-digit. The two digits, read together, give the letter's position counted backward from Z (position from Z = 27 minus position from A). Across the series, the letters themselves advance by a fixed number of places in the alphabet.

1. E is the 5th letter from A, so its position from Z is 27 minus 5 = 22; splitting the digits 2 and 2 around E gives the term 2E2.

2. H is the 8th letter from A, so its position from Z is 27 minus 8 = 19; splitting 1 and 9 around H gives 1H9.

3. K is the 11th letter from A, so its position from Z is 27 minus 11 = 16; splitting 1 and 6 around K gives 1K6.

4. N is the 14th letter from A, so its position from Z is 27 minus 14 = 13; splitting 1 and 3 around N gives 1N3.

5. The letters E, H, K, N each advance by 3 places in the alphabet, so the next letter is Q (14 + 3 = 17th from A).

6. Q's position from Z is 27 minus 17 = 10; splitting the digits 1 and 0 around Q gives 1Q0.

Cross-check: The letters E, H, K, N advance by exactly 3 places each time, and every term's digit pair matches its letter's position from Z, so extending the same +3 step and re-encoding the position from Z confirms the missing term.

Correct option: 1Q0.