What network does Iphone 5c from net10 and straight talk work off of?

I was wondering if AT&T or Verizon works off of Iphone 5c from net10 or straight talk

The thing is that Net10 and Straight Talk use both the CDMA and GSM cellular networks for their phones, so it really depends on your IPhone 5C if it's the CDMA or GSM version.

Here's the Apple website to find out.
http://support.apple.com/.../kb/ht3939

If it is the CDMA version then it is compatible with AT&T's network. If it is the GSM version then it is compatible with Verizon's network.