Find the incorrect part of the sentence:
She is better in mathematics than English.

Correct option is D

Option (d) contains an error.
Explanation: With adjectives like good/bad/better/best, we use the preposition at for subjects/skills: good at, better at, best at. So it should be “better at mathematics”, not “better in mathematics.”
Corrected sentence: She is better at mathematics than English.
Grammatical rule used:
· Use at with activities/skills/subjects after evaluative adjectives: good at chess, weak at physics, better at coding.
· Use in mainly for areas/fields/locations ( in the field of mathematics, in the class), not after better to denote skill.
· Example: Rita is good at English but weak at Chemistry.
· Info booster:
· In is acceptable in phrases like “a degree in Mathematics”, but after “good/better/best” to indicate competency, prefer at.