The figure above shows Bill's Hotdogs, a monopolistically competitive firm. If other firms enter the market and have hot dogs that are very close substitutes for Bill's Hotdogs, then the demand curve for Bill's Hotdogs will ________.
选项：

A: shift leftward and become more elastic
B: shift rightward and become more elastic
C: shift rightward and be parallel to the original demand curve
D: shift leftward and be parallel to the original demand curve