Scooters and Bicycles Are Substitutes

Scooters and bicycles are substitutes. Suppose the price of a bicycle falls. Which of the figures above best illustrates how this fall in price affects the demand curve for scooters?

A) Figure A
B) Figure B
C) Figure C
D) Figure D
E) None of the above answers is correct because the change in the price of a bicycle will affect the supply curve NOT the demand curve.