Answer:
(c) an = 4·(1/3)^(n-1)
Explanation:
The explicit rule for a geometric sequence with first term a1 and common ratio r is ...
an = a1·r^(n-1)
The factor in the recursive rule tells you the common ratio is 1/3, so the explicit rule is ...
an = 4·(1/3)^(n-1) . . . . . . matches choice C