根据对话内容，从对话后的选项中选出能填入空白处的最佳选项，并将答案标号填写在答题卡上相应题号后的横线上。选项中有两项多余选项。

A：Frank，it’s almost vacation time．Have you found a summer job yet?

B： 小题1:  But camp job doesn’t pay much．How about you?

A：Well，I think I can get a j ob at the Friendship Hotel．A friend of mine was a waiter there last summer．The pay wasn’t good，but he got a lot of tips．He was happy with it．

B： 小题2: She enjoyed it．She said a restaurant was a good place for her．

A：小题3:After sitting in school classes all winter，I'd like a job in open air．

B：You are right．Everybody knows high school kids earn a lot just by cutting grass every summer．My brother is only fifteen，but he gets eight dollars every time he cuts somebody’s grass．It takes him only an hour!

A：小题4:But now，I think I might work for a building company，or something like that．

B：小题5:You can learn a 10t．

A：Well，I'd like to have a try．

假设某企业生产甲、乙、丙三种产品，各产品的贡献毛益率分别为10%、15%和30%，销售比重分别为30%、30%和40%，则该企业综合的加权贡献毛益率为（）。

A.55%

B.19.5%

C.15%

D.30%