Suppose Several Industries Compete for the Available Supply of a Particular

Multiple Choice

Suppose several industries compete for the available supply of a particular input.In a multi-industry market like this,which of the following statements about the input supply curve facing a single industry will be true?

A) Each industry's input supply curve is an equal proportion of the total market supply of the input.
B) The vertical summation of the industry input supply curves gives the market supply curve for the input.
C) The smaller the share of the total input employed by the industry,the more elastic its input supply curve.
D) The input supply curve for a single industry in a multi-industry input market is perfectly elastic over all levels of employment of the input.