The following sentence has been split into four segments. Identify the segment that contains a grammatical error.
It is difficult to say / which of the / two girls in that house / is the eldest.

Correct option is C

Option (c) contains an error.
Explanation:
The superlative “eldest” is used within a family. But the error here is contextual and grammatical – when comparing only two, we use comparative degree, not superlative.
Correct form: “is the elder.”
Grammatical Rule Used:
· Use “elder” (or “older”) when comparing two persons.
· “Eldest” is only used for three or more.
Example:
Incorrect – She is the eldest of the two sisters.
Correct – She is the elder of the two sisters.
Information Booster:
· “Elder” and “eldest” are used only for people (not objects), usually within families.