Select the most appropriate idiom for the highlighted phrase.
Many students are not able to decide their course of action.

Correct option is A

The correct idiom for "not able to decide their course of action" is (a) On the fence.
Explanation: The idiom "on the fence" means to be undecided or unable to make a decision about something. Here, it fits well as it conveys that many students have not yet made up their minds regarding their course of action.
Example Sentence:
· Many students are on the fence about which career path to pursue after graduation.
Meanings of all other options:
· As pale as a Ghost: Looking very pale, often due to fear or illness.
· Example: He turned as pale as a ghost after hearing the shocking news.
· On cloud nine: Extremely happy or delighted.
· Example: She was on cloud nine after receiving the promotion.
· Green thumb: Having a natural talent for gardening.
· Example: With his green thumb, his garden is always in full bloom.