Select the sentence that has a grammatical error.

Correct option is D

Option (d) "An university is defined by its pupils" contains the grammatical error. The error lies in the incorrect use of the article "an" before "university." The correct article should be "a" because "university" begins with a 'y' consonant sound.
· Grammatical rule used: The article "a" is used before words that begin with a consonant sound, while "an" is used before words that begin with a vowel sound. Example: He attends a university in the city.