In a Perfectly Competitive Market,a Firm's Rental Rate for a Machine

In a perfectly competitive market,a firm's rental rate for a machine (v) will be given by:
Where r is the prevailing rate of interest and d is the depreciation rate.In this formula,p represents:

A) the present market price of the machine.
B) the initial purchase price of the machine (assuming this differs from its present market price) .
C) the price of the firm's product.
D) the depreciated value of the machine.