In my opinion answer is C. As Either the term could be 7 or 77. And sumof all the terms could be 350 only. Case1: If there is one 77 term in the series then 350-77=273. And as 273/7=39. So there will be 39, 7 terms and one 77 term. in total 40 term in the series. Case 2: If there are two 77 terms in...