If the fifth term in a geometric sequence is 1∕27 and the common ratio is 1∕3, find the explicit formula of the sequence.
 Question 18 options:
 A) 
 an = (1∕3)n – 1 for n ≥ 1
 B) 
 an = (1∕27) ⋅ (1∕3)n – 1 for n ≥ 1
 C) 
 an = (3) ⋅ (1∕3)n – 1 for n ≥ 1
 D) 
 an = (3) ⋅ (3)n – 1 for n ≥ 1