20
25
35
30
Answer is Right!
Answer is Wrong!
The correct answer is D. 30.
The answer is based on the following rule:
- During all communication failure, the second train shall be dispatched after an interval of 30 minutes.
This rule is in place to ensure that there is a safe distance between trains in case of a communication failure. If the trains were to be dispatched too close together, there would be a risk of a collision.
The other options are incorrect because they do not meet the requirements of the rule. Option A is too short, Option B is too long, and Option C is not a multiple of 30.