Hi i was jsut looking for a little help for my AP Bio class im taking. I think that i am just trying way to hard to solve a simple problem. If anyone has time i would much appreciate the help.

The problem states "Show all differnt kinds of gametes which could be produced by the following individulas"

And here is what is given: CcDd

I tried normaly crossing this, but i could have sworn the teacher said there was supposed to be 16 gametes. Just a little help and description on how to solve this is all i ask. Thanks a ton