In any sequence of ~$n$~ nonzero numbers, a pair of consecutive terms with opposite signs represents a sign change. For example, the sequence -2, 3,-4, 5 has three sign changes. Does the sequence of nonzero numbers ~$s_1,s_2,\ldots, s_n$~ have an even number of sign changes?

1. ~$s_k = (-1)^k$~ for all positive integers ~$k$~ from 1 to ~$n$~.

2. ~$n$~ is odd.

Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

EACH statement ALONE is sufficient.

Statements (1) and (2) TOGETHER are NOT sufficient.