Select the most appropriate idiom that can substitute the highlighted words in the given sentence.
It was a difficult task to complete a relay run of 5 km in minutes yet our team managed to do it successfully.

Correct option is B

Option (b) is the correct idiom of the highlighted word.
A Herculean effort- A difficult task.
Idiom used in a sentence: Despite the challenging circumstances, she made a Herculean effort to complete the project ahead of schedule.