Explanation:

- To solve the problem, we need to find pairs of letters in "REVOLUTION" that maintain the same number of letters between them as in the English alphabet sequence.

- Let's explore each possibility:

1. R and V: There are 3 letters between them both in the word and the alphabet (S, T, U).

2. E and O: There are 7 letters between them both in the word and the alphabet (F, G, H, I, J, K, L).

3. V and N: The letters V and N have 5 letters in between both in the word and the alphabet (W, X, Y, Z, A - considering N, O, P, Q, R as skipped in a continued alphabet sequence from V to N in reverse).

4. U and O: There are 5 letters between them both in the word and the alphabet (V, W, X, Y, Z followed by A, B, C – only O is counted after a new alphabet cycle).

- After checking different combinations and verifying their positions in the word and the alphabet, we only list: R and V, E and O, V and N, U and O.

- Therefore, Option:4 - Four is the correct answer.