Organ donation and religious discrimination?

[magpieix C.A.C.T.U.S.]

So I'm filling out my renewal for my driver's license and when I got to the part about "In the even of a fatality do you wish to donate your body?". But there's only two choices--"transplant" and "medical research". So I call up the DMV and I ask then where the check box for "food bank" is, and the woman gives me a hard time and hangs up. I suspect that this is because the food bank in my town is operated by nuns and the DMV is interfering with my freedom of religion. How can they get away with letting atheists donate their bodies to "science" while honest, god-fearing folks can't donate their body to a worthwhile Christian charity? Is this fair?

Thanks in advance.