He often makes a mountain out of a molehill.What does the underlined idiom mean?

Explanation

The idiom 'mountain out of a molehill' means to exaggerate a small problem, making it seem much larger or more significant than it actually is. In this context, the phrase highlights the tendency of some people to blow minor issues out of proportion. The other options do not capture this meaning: Option A suggests hard work, which is unrelated; Option C takes the phrase literally, focusing on climbing; and Option D implies challenges in nature, which also strays from the idiomatic meaning.