Write the geometric sequence in function notation. 4, 2, 1, 1/2, 1/4, ..
a) f(x) = (2) ⋅ (1/4)x – 1
b) f(x) = (4) ⋅ (1/4)x – 1
c) f(x) = (2) ⋅ (1/2)x – 1
d) f(x) = (4) ⋅ (1/2)x – 1