This question is based on the following table.

Household Income Average number of car per household

$0 --- $29,999 1.3

30,000 --- 49,999 1.7

50,000 --- 74,999 2.3

75,000 --- 99,999 2.8

100,000 --- 149,999 3.4

150,000 and over 3.7

The relationship between household income and average number of car per household is:

Group of answer choices

a. Fluctuating.

b. Direct.

c. Indirect.

d. Terminal.

e. Nonexistent.