Brass is an alloy composed primarily of copper and zinc and appears macroscopically uniform. Which classification and reasoning are most consistent with its composition?
a) Brass is a pure element because it consists solely of metal atoms.
b) Brass is a homogeneous mixture because it contains two different metallic elements distributed uniformly at the atomic level.
c) Brass is a pure compound because the copper-to-zinc ratio is constant throughout the sample.
d) Brass is a heterogeneous mixture because the different metals remain in separate phases inside the alloy.