I need to get new back tires. The front ones are still ok. When I get the new ones should I:

A. Put them on the front and move the good ones I have on the front, to the back?
or
B. Put the new tires on the back and wait until the ones on the front get bad before putting the new ones on the front?

Which is a better option? It's front wheel drive so I'm thinking option A is a better idea but I'm not sure.