Select the verb to fill in the blank in the following sentence:-

It wasn't the first time they had been _____ how it worked.

taught

The correct answer is Option (3) → taught

The sentence structure "had been _____ how it worked" requires a passive verb that conveys the transmission of knowledge or instruction.

Taught: Means to impart knowledge to or instruct (someone) on how to do something. This fits the context perfectly, as the function of the object ("how it worked") is being explained.

Why the other options are incorrect:
Reported– means informed or announced, not instructed.
Exclaimed– means cried out loudly; meaningless here.
Inferred– means concluded from evidence; does not fit the structure “had been inferred.”