Mapple is a smartphone producer who operates its own stores and directly sells its products to its customers. The variable cost of their smartphone is $200, which Mapple sells at 300% markup.

Recently, Mapple decided to sell some of its smartphones through another retailer. Accordingly, they sell their smartphones to a wholesaler at 25% markup, who then sells the smartphone to the retailer at 50% markup. If the retailer intends to sell these smartphones at the same price as Mapple does in their Mapple stores, what is the contribution margin ($) of the retailer?

a 325

b 425

c 625

d 525