Select the option that will improve the highlighted part of the given sentence. In case no improvement is needed, select 'No improvement required'.
While the symptoms are troubling, they typically resolve within two weeks.

Correct option is A

The correct substitution of the highlighted words is (a) No improvement required.
The given sentence is grammatically correct.
The subject "symptoms" is plural, so the plural verb "are" is correctly used.
The word "troubling" is an adjective that correctly describes the symptoms as causing concern.
Grammatical Rule Used: Subject-Verb Agreement – Plural subjects require plural verbs.
Example: The side effects are troubling but usually disappear after a few days.
Meanings of other options:
· Was troubling: Incorrect as "was" is singular, but "symptoms" is plural.
· Is troubling: Incorrect as "symptoms" is plural and requires "are".
· Are troubled: Incorrect as "troubled" would mean "symptoms themselves are disturbed," which does not fit the context.