Marjorie is conducting a science experiment to measure the amount of pollution produced by cars that used gasoline containing different amounts of lead. Identify the dependent and independent variables.

a: i= conducting a science experiment
d= the amount of pollution
b: i= the amount of pollution
d= gasoline containing different amounts of lead
c: i= gasoline containing different amounts of lead
d= type of car
d: i= gasoline containing different amounts of lead
d= the amount of pollution

The independent variable is the gasoline containing different amounts of lead. The dependent variable is the amount of pollution produced by the cars using the different types of gasoline. Therefore, the correct answer is d: i= gasoline containing different amounts of lead, d= the amount of pollution.