Tell whether the sequence 1/3, 0, 1, -2 ... is arithmetic, geometric, or neither. Find the next three terms of the sequence.

A. neither; 7, -20, 61
B. geometric; 7, -20, 61
C. arithmetic; -1/3, 1 1/3, 3
D. geometric; -3 1/3, -5 5/9, -9 7/27