NQE should come in place of the question mark (?).
To find the missing term, let's look at the pattern for each letter position across the terms in the series:
1. First Letter Position: T →R→P→?→ L
• T (20) −2→ R (18)
• R (18) −2→ P (16)
• P (16) −2→ N (14)
• N (14) −2→ L (12)
2. Second Letter Position: Y →V→S→?→ M
• Y (25) −3→V (22)
• V (22) −3→S (19)
• S (19) −3→ P(16)
• Q (16) −3→M (13)
3. Third Letter Position: H →G→F→?→D
• H (8) −1→ G (7)
• G (7) −1→ F (6)
• F (6) −1→E (5)
• E (5) −1→ D (4)
Combining the letters gives NPE.