If the cross elasticity of demand between two goods is negative, * A. ONE OF THE GOODS MUST BE INFERIOR. * B. THE TWO GOODS ARE COMPLEMENTS. * C. ONE OF THE GOODS MUST BE A NECESSITY. * D. THE TWO GOODS ARE SUBSTITUTES.

If the cross elasticity of demand between two goods is negative,

*  A. ONE OF THE GOODS MUST BE INFERIOR.
*  B. THE TWO GOODS ARE COMPLEMENTS.
*  C. ONE OF THE GOODS MUST BE A NECESSITY.
*  D. THE TWO GOODS ARE SUBSTITUTES.