Choose the idiom/phrase that can substitute the highlighted group of words meaningfully.
I worked for hours on that project but now it is cancelled. All my hard work has been wasted.

The correct answer is (b) Gone down the drain.
Explanation:
The idiom "gone down the drain" means wasted effort or something that has been rendered useless, which perfectly substitutes for "All my hard work has been wasted."
Meanings of all options:
· Beat the drum: To promote or publicize something enthusiastically.
· Gone down the drain: Wasted or rendered useless.
· In the same boat: In the same situation, typically a challenging one.
· Through thick and thin: Under all circumstances, no matter the difficulties.