I had this exact problem with the same hardware. Laptop + m-audio
firewire 410. I did ( b.)
I cut the the wires from the earth pin - central pin and voila noise is
gone.
Apparently laptops are low power so u wont fry yourself or the hardware
if u try it. I was humming and hawing(no pun ;) about this for months
before I did it, for the exact reason of not being crazy about frying
myself or laptop but it works and I've loads of plugs plugged into the
same board.
I didnt go for a ground loop because the ground loops on offer only
come with rca i/o while the 410 has 1/4 inch jacks, which are better. It
meant more cables also and I've enough already all over the place!
Go for option (b.) I reckon.