【正确答案】 A

【答案解析】20X7 gross profit is equal to $100 million ($1×250 million units sold×40% gross profit margin). The 10% price cut to $ 0.90 will increase cost of goods sold to 67% of sales [COGS= 0.6×$1=$0.60; $0.60/$0.90=67%]. As a result, gross profit will decrease to 33% of sales. If unit sales double in 20X8, gross profit will equal $150 million ($0.90×500 million units×33% gross profit margin). Therefore, gross profit will increase $50 million ($150 million 20X8 gross profit -$100 million 20X7 gross profit).