Select the alternative that will improve the highlighted part of the sentence. In case there is no improvement select “No improvement”.
The manager could not able to understand the problem the factory workers faced.

Correct option is C

The correct substitution of the highlighted part is (c) was not able to.
Explanation:
· “Could not able” is grammatically incorrect.
· “Could” is already a modal verb, and combining it with “able to” is redundant.
· Correct form: was not able to (past ability)
Grammatical Rule Used:
“Could not” and “was not able to” express inability, but never combine “could” with “able to.”
Example:
· Incorrect: I could not able to solve the question.
· I was not able to solve the question.