Create a uniform (constant & parallel) magnetic field in a small volume of space. The field should be .5 tesla, equal to the strength of the Earth's magnetic field. you can get a current of 2 Amperes from a power source, and you must choose one of the following methods:
a) in between two long parallel wires spaced distance 2D apart
b.) a long solenoid of length l and N turns
c.) a single long straight wire at distance r from the wire
d.) a flat coil of radius R and N turns