11. Here we are asked to consider what might cause own price elasticity to change in value. In this case, elasticity changes from .75 to 1.25; that is, it goes from being inelastic to elastic. We know if the demand curve is linear, an increase in price causes demand to become more elastic, however this is not given as one of the choices. If supply shifts back or decreases this could also cause price to rise, but there is no such choice available either. Demand can become more elastic due to the introduction of a substitute. This is the correct answer.