求讲解,要详细,每个选项为什么选,为什么不选,求详细!（定语从句）

Whenener I met her,------was fairly often ,she greeted me with a sweet smile.(B)

A.who B.which C.when D.that

She brought with her three friends,none of I had ever met before.(C)

A.them B.who C.whom D.these

Because of the financial crisis,days are gone------ local 5-star hotels charged 6,000 yuan for one night.(B)

A.if B.when C.which D.since

A person-------e-mail account is full won't be able to send or receive any e-mails.(C)

A.who B.whom C.whose D.whoever

Gun control is a subject------Americans have argued for a long time.(C)

A.of which B.with which C.about which D.into which

Mozart's birthplace and the house-------he composed "The Magic Flute" are both museums now.(A)

A.where B.when C.there D.which

The house I grew up-----has been taken down and replaced by an office building.(B)

A.in it B.in C.in that D.in which