In a Small Kansas Town, There Are Two Kinds of Gasoline

In a small Kansas town, there are two kinds of gasoline consumers: 100 Buick owners and 50 Dodge owners. Each Buick owner has the demand function D_b(p) = max{ 0, 20 - 5p} and each Dodge owner has the demand function D_d = max{ 0, 15 - 3p}. In this town, the market demand curve has

A) no kinks but gets steeper as price rises.
B) no kinks but gets flatter as price rises.
C) constant slope since individual demand curves have constant slope.
D) a kink at p = 4 and another at p = 5.
E) a kink at p =.