GMAT Sentence Correction (SC) | Re: To force a person to retire solely because they have

To set the context, the sentence is trying to compare two actions - forcing a person and denying.

Errors: Parallelism and Pronoun.

Option A (incorrect): To force a 'person'...because 'they' is wrong (antecedent for 'they' should be plural). Denying is a verb and should have parallel construction with 'forcing'.
Option B (incorrect): Pronoun error (as explained for options A).
Option C (incorrect): Parallel construction error of 'forcing' and 'to deny'.
Option D (CORRECT): Corrects pronoun and
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