My solution: By a theorem, I know that the unique subgroup of order 10 is <40/10> = <4> = {0,4,8,12,16,20,24,28,32,36>
So are those the answers?
Think about it. It has to have ten members and it has to be closed and it has to include 0. That's going to be awfully hard to do with a different subset than the one you listed.