Patrick Lives near Two Petrol Stations, Caltex and Shell

Multiple Choice

Patrick lives near two petrol stations, Caltex and Shell. If Caltex decreases the price of petrol, we predict that the quantity of petrol demanded at Shell will

A) decrease because Caltex and Shell petrol are substitutes.
B) decrease because Caltex and Shell petrol are complements.
C) increase because Caltex and Shell petrol are substitutes.
D) increase because Caltex and Shell petrol are complements.
E) not change because Caltex and Shell are different brands of petrol.