The correct answer is: Both I and II follow.
The statement provides evidence that there have been many instances of derailment of trains due to landslide in the hilly areas. This suggests that there is a problem with the stability of the hill slopes in these areas. The two courses of action address different aspects of this problem.
Course of action I proposes to deploy pilot engines before the movement of passenger trains in the hilly areas. This would allow the train to be warned of any landslides that may occur ahead, and to take evasive action if necessary. This would help to prevent derailments caused by landslides.
Course of action II proposes to strengthen the hill slopes by putting iron meshes so that the loose boulders do not fall on the track. This would help to prevent landslides from occurring in the first place. This would also help to prevent derailments caused by landslides.
Both courses of action would help to reduce the risk of derailment due to landslides. Therefore, both I and II follow.
Here is a more detailed explanation of each course of action:
Course of action I: Deploying pilot engines before the movement of passenger trains in the hilly areas would allow the train to be warned of any landslides that may occur ahead, and to take evasive action if necessary. This would help to prevent derailments caused by landslides.
Course of action II: Strengthening the hill slopes by putting iron meshes so that the loose boulders do not fall on the track would help to prevent landslides from occurring in the first place. This would also help to prevent derailments caused by landslides.
Both courses of action would help to reduce the risk of derailment due to landslides. Therefore, both I and II follow.