Hazrat Usman (RA) is called "Zun-Nurain" because:
Correct answer: B. He married two daughters of the Holy Prophet (PBUH)
"Zun-Nurain" means "possessor of two lights": he married Hazrat Ruqayyah (RA) and, after her death, Hazrat Umm Kulthum (RA).
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