Which sequence is geometric and has 1/4 as its fifth term and 1/2 as the common ratio?
A. 1, 1/2, 1/4, 1/8
B. 1/4, 1/2, 1, 2
C.1/72, 1/36, 1/18, 1/9
D. 8, 4, 2, 1