Simplify the following Boolean function, using three-variable maps: (f₁(x, y, z) = ∑(1, 2, 3, 7)).
a) (xyz' + xy'z' + x'yz' + x'y'z)
b) (xyz + xy'z' + x'yz' + x'y'z)
c) (xyz + xy'z' + xyz' + x'y'z)
d) (xyz' + xy'z' + xyz' + x'y'z')