Select the most appropriate meaning of the given idiom.
A hard nut to crack
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. A problem that is difficult to solve.
Idiom: A hard nut to crack
Meaning: A difficult problem or situation that is tough to deal with.
Example: Solving this complex mathematical equation is a hard nut to crack.
Hence, the chosen option is correct.