In 2009, an agricultural company introduced a new cropping process which reduced the cost of growing some of its crops. If sales in 2008 was $25 million and in 2009 was $30 million, but the gross margin changed from 4.0% to 5.0% between those years, by what amount was the cost of sales changed? Select one: a. $0.30 million ho b. $-0.25 million c. $4.50 million d. $5.05 million