The road is covered with snow. I can’t understand ______ they insist on going by motorbike.

A．why

B．whether

C．when

D．how

广播电台、电视台、报刊出版单位的广告业务，应当（）

A.依法办理兼营广告的登记

B.广告业务由专门从事广告业务的机构办理

C.可由多个部门从事广告业务

D.由总编室负责经营广告业务