### Isomorphic groups

I am trying to learn this material on my own to prepare for a future graduate course. I would like to see the solutions to this problem to have something to imitate when working other problems. Decide which (if any) of the following are isomorphic to which: (a) D3xS4 (b) D6xA4 (c) D4xD9 Dn=dihedral group of order 2n, A