Which line from the text states that the narrator was young at the time?

By one of those caprices of the mind which we are perhaps most subject to in early youth. . .
I at once gave up my former occupations, set down natural history and all its progeny as a deformed and abortive creation. . .
In this mood of mind I betook myself to the mathematics. . .
. . .the branches of study appertaining to that science as being built upon secure foundations, and so worthy of my consideration.

Question

Which line from the text states that the narrator was young at the time?

 By one of those caprices of the mind which we are perhaps most subject to in early youth. . .
 I at once gave up my former occupations, set down natural history and all its progeny as a deformed and abortive creation. . .
 In this mood of mind I betook myself to the mathematics. . .
 . . .the branches of study appertaining to that science as being built upon secure foundations, and so worthy of my consideration.

4801651310 · Answer

I think its C but not really sure

candycove · Answer

I don't know this one. :(