Demand for Barbara Streisand CDs Is Equal to Q_s =

Demand for Barbara Streisand CDs is equal to Q_s = P^1.70_sI^2.20P^1.80_c, where Qs is the number of CDs, P_s is the price of a Streisand CD, I is per capita income, and Pc is the price of a Karen Carpenter CD. Streisand and Carpenter CDs

A) are inferior goods.
B) are complements.
C) are substitutes.
D) have diminishing returns to scale.
E) are not as good as the original 8-track tapes.