Nathan Johnson has surveyed a group of companies on their needs for computer keyboards and the prices the companies are willing to pay. Based on this survey, he has developed an idea for a fatigue reducing keyboard that can be reasonably priced at $500. Nathan believes that this particular product should allow a profit of 25 percent of the product's cost. Calculate Nathan Johnson's target cost for his keyboard. a. $750 b. $300 O c. $400 d. $500