According to Kant,sometimes We Use People to Achieve Some End,yet

According to Kant,sometimes we use people to achieve some end,yet our actions are not wrong because:

A) every situation is different.
B) exceptions are made for people who are not our friends.
C) there is no moral difference between treating persons as a means and treating them merely,or only,as a means.
D) there is a moral difference between treating persons as a means and treating them merely,or only,as a means.