The following sentence has been split into four segments. Identify the segment that contains a grammatical error.
She can’t come for lunch / with you. / She’ll do some / training in the gym.

Correct option is C

Option (c) contains an error.
The segment "She'll do some" could be seen as grammatically incomplete or vague when used with "training." A more precise and contextually appropriate phrase would be "She has to do some training," which implies obligation or necessity rather than a simple statement of action. This adjustment in wording better explains her inability to come for lunch, as it highlights the necessity of the training rather than just an activity she will undertake.
Grammatical rule used: Use of "has to" to express obligation or necessity, providing a clearer explanation for why she cannot participate in another activity.