Question

review the passage. the allusion is shown in bold.
the engineer had listened to the enthusiastic sailor developing these imaginative projects. to attack this mass of granite, even by mining, was a herculean task, and it was truly vexing that nature had not helped them in their necessity. but he answered pencroff, simply by proposing to examine the wall more attentively, from the mouth of the river to the angle which ended it to the north.
from jules verne, journey to the centre of the earth
what is the effect of the allusion on the passages meaning or tone?
it suggests that the task is a thankless one.
it highlights how important this project is.
it highlights the projects extreme difficulty.

Explanation:

The allusion "Herculean" refers to the great strength and immense difficulty of the tasks performed by the Greek hero Hercules. In the context of attacking a mass of granite, this allusion conveys that the project is extraordinarily hard to complete.

Answer:

It highlights the project's extreme difficulty.