Explanation:

- Volleyball games are played in sets. Typically, a match is best-of-five sets.

- For the first four sets, a team must score 25 points and be at least 2 points ahead to win that set.

- If the match goes to a fifth deciding set, the set is played to 15 points, with at least a 2-point lead.

- Each set beyond the second follows this scoring pattern, including the 4th set.

- Therefore, in the 4th set, teams must reach 25 points with at least a 2-point margin to win.

Option:3 - 25

.