In Problems 1 and 2, determine whether the indicated sequence can be the first three terms of an arithmetic or geometric sequence, and, if so, find the common difference or common ratio and the next two terms of the sequence.
(A) 5, 20, 100, ...
(B) -5, -5, -5, ...
(C) 7, 6.5, 6, ...
(D) 512, 256, 128, ...