(-a)n is negative If is a real number and is a positive integer, which of the following represents all values of and such that the above statement is true?

A. {a | a is positive.} and {n | n is odd}

B. {a | a is negative} and {n | n is even}

C. {a | a is positive} and {n | n is even}

D.{a | a is negative} and {n | n is odd}