Select the most appropriate meaning of the given idiom.

Needle in a haystack

Something impossible to find

The most appropriate meaning of the idiom "needle in a haystack" is something impossible to find.

The other options are incorrect.

• "Someone having vast opportunities" is not the same as a needle in a haystack. Someone having vast opportunities has many chances to succeed, while a needle in a haystack is something that is very difficult to find.
• "Someone in trouble" is not the same as a needle in a haystack. Someone in trouble is in a difficult situation, while a needle in a haystack is something that is very difficult to find.
• "Something very trivial" is not the same as a needle in a haystack. Something very trivial is something that is not important, while a needle in a haystack is something that is very difficult to find.

The idiom "needle in a haystack" comes from the idea of finding a needle in a large pile of hay. This would be a very difficult task, as the needle would be very small and the hay would be very large. In the same way, something that is a needle in a haystack is something that is very difficult to find. For example, you might say that a lost contact lens is a needle in a haystack.