Explanation:

Let's analyze the given letter series:

A C D F G I J L M O P ?

Step 1: Identify the pattern

Break the sequence into positions in the alphabet:

• A (1), C (3), D (4), F (6), G (7), I (9), J (10), L (12), M (13), O (15), P (16), ?

Observing the pattern, we notice:

1. The letters are selected in a specific sequence with varying gaps.
2. The gaps between consecutive letters are:
   • A → C (+2)
   • C → D (+1)
   • D → F (+2)
   • F → G (+1)
   • G → I (+2)
   • I → J (+1)
   • J → L (+2)
   • L → M (+1)
   • M → O (+2)
   • O → P (+1)
   • P → R (+2)

Step 2: Find the missing letter

Following the pattern (+2, +1, +2, +1, ...), the missing letter after P should be R.

Correct Answer:

(D) R