Explanation:

- The boxes are A, B, C, D, P, and Q, arranged one above the other.

- A is placed just adjacent to D and contains 30 pencils.

- Since A and C have one box between them, and A is adjacent to D, A must be either at the 2nd or 3rd position.

- If A is second, D is at the bottom. That makes C be 4th and P at the 3rd position.

- Q is placed just above D. If D is at the bottom, Q is right above D.

- B is not at the top. Therefore, we can place B at the position of P.

- Given the sequence of pencils, positions are 6, 12, 18, 24, 30, 36 pencils respectively ascending.

- As per pencil distribution, P will have 36 pencils being top, and C would be the 6-pencil box.

- Hence, the topmost box becomes apparent as P.

So, based on the given instructions, your answer is incorrect. The top box must be: Option: 2, P

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