题目

Last year,around Labor Day,I read a Happy Ad in our local newspaper.There was a lady in a local nursing home for the aged,who was celebrating her 90th birthday and her family wanted everyone to know about it.It said that if you wanted to drop her a line,here was her address.So I did.I found a birthday card and dropped her a short note,wishing her a happy birthday. A week or so later,someone knocked at my front door.I opened the door and found a middle-aged man standing on my doorstep.He introduced himself as the son of this woman to whom I had sent the card.He explained that he just 已知函数y=Asin（ωx+φ）+k的最大值是4，最小值是0，最小正周期是，直线是其图象的一条对称轴，则下面各式中符合条件的解析式是（ ）A．B．C．D．