|A) Neither a nor b is sufficient||B) Either a or b is sufficient|
|C) Both a & b are sufficient||D) a alone is sufficient while b alone is not sufficient|
From a, we conclude that Vinitha is the wife of Ragini's mother's only son i.e. Ragini's brother. Thus, Vinitha is Ragini's sister-in-law.
From b, we conclude that Vinitha is the cousin of Ragini's husband, which implies that Vinitha is Ragini's sister-in-law.