A:in place
B:in sight
C:in effect
D:in vain.
某商品的进价为每件40元,售价为每件50元,每个月可卖出210件.如果每件商品的售价每上涨1元,则每个月少卖10件.当每件商品的售价定为多少元时,每个月的利润恰为2200元?
— Because I just want to join my husband's company and give him support.