单选题 What does unwanted e-mail messages do to the providers of the Internet services?

A、 Raising their cost.
B、 Raising the Internet speed.
C、 Improving their business.
D、 Attracting investment.

【正确答案】 A

【答案解析】[分析] 细节题型。见第四段第一句：The growth in unsolicited commercial electronic mail imposes significant monetary costs on providers of Internet access services，businesses，and educational and nonprofit institutions that…因此选项A是答案。