If it is possible to make only one meaningful word from the 2nd, 4th, 5th and 6th letters of the word “DISCOVER” using each letter only once, then what is the last letter of the word. If no such meaningful word can be formed the answer is “X” and if more than one such meaningful word can be formed, the answer will be “Z”?

The correct option is X.

Step 1: Identify the specified letters from the given word.
The given word is "DISCOVER". Let's number each letter according to its position:
1st letter = D
2nd letter = I
3rd letter = S
4th letter = C
5th letter = O
6th letter = V
7th letter = E
8th letter = R

Step 2: Extract the required letters.
We need the 2nd, 4th, 5th, and 6th letters:
- 2nd letter: I
- 4th letter: C
- 5th letter: O
- 6th letter: V

The extracted letters are I, C, O, and V.

Step 3: Check for meaningful English words.
We attempt to form a meaningful four-letter word using each of the letters {C, I, O, V} exactly once.
None of the arrangements (e.g., CIVO, VICO, OVIC, COVI, etc.) form a standard, valid English dictionary word.

Step 4: Determine the final answer based on the rules.
According to the instructions given in the question:
- If no meaningful word can be formed, the answer is "X".
- If more than one meaningful word can be formed, the answer is "Z".

Since no meaningful word can be formed using the letters I, C, O, and V, the required answer is X.