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 the projects extreme difficulty.
it highlights how important this project is.

Explanation:

The term "Herculean" refers to tasks as difficult as those performed by the Greek hero Hercules. Here, it emphasizes the extreme difficulty of attacking the mass of granite.

Answer:

It highlights the project's extreme difficulty.