Select the option that can be used as a one-word substitute for the given group of words.
A problem that is so difficult that it cannot be answered
Answer & explanation
Correct answer: option 2
The correct option is insoluble. It means "impossible to solve." The other options are not correct substitutes.
- Impossible means "unable to be done or achieved."
- Terrible means "extremely bad or unpleasant."
- Solvable means "able to be solved."