As they waited, Rahim argued against war ‒

A while his brother discusses the effects of pollution

B while his brother discussed the effects of pollution

C while his brother was discussing the effects of pollution

D while his brother had discussed the effects of pollution

Correct Answer: Option C

While দ্বারা কোনো Sentence বা Clause শুরু হলে While এর পরেই subject থাকলে Verb এর Past Continuous হয়। তাই গ-ই ঠিক।