为自己加油

My brother stayed in Hong Kong for five months, during which time l often wrote him letters.

A.我哥哥在香港呆了五个月，期间我经常给他写信。
B.我经常给他写信，在我哥哥呆在香港的五个月里，。
C.我哥哥在香港呆的五个月里我经常给他写信。
D.我哥哥经常收到我写的信在香港呆的五个月里。