The following sentence has been split into four segments. Identify the segment that contains a grammatical error.
She needed a break then / because she had solved / mathematical problems / all morning.

Correct option is A

Option (a) “because she had solved” contains an error in tense usage.
The phrase “all morning” shows an action continuing for a duration up to a point in time, so we generally use Present Perfect Continuous (if connected to present) or Past Perfect Continuous (if connected to a past point). Here, “She needed a break then” is past, so the action should be shown as continuing up to that past moment: “had been solving”, not “had solved”.
Correct sentence: She needed a break then because she had been solving mathematical problems all morning.
Grammatical rule used:
· For an activity continuing for a period of time up to a past point, use Past Perfect Continuous: had been + V1 + ing.
Example (rule):
· He was tired because he had been working for six hours.
Information booster:
· Past Perfect (had + V3) is used more for a completed action before another past action, often with a clear completion/result.
· Past Perfect Continuous (had been + V-ing) highlights duration/continuity, commonly with “for/since/all day/all morning.”