Hi .. Very interesting question.. It check your basic understanding with number system .
1) 1+n > 0
It means n can not be less than Zero ... then only this condition will true. n can be { 0,1,2,3,.. etc}. A along can not answer the question move to second choice
2) np>0
It means either both are positive or both are negative(p can be +ve or -ve) ... so still we can not answer the question ...
let's combine both ... from 1 we can say n > 0 means p is also positive than only its true.. Hence answer is C ..
Hope this will help you to understand ...