questions about cos distance

[soldier828]

I just start to learn DEEPID using caffe, and I wonder when I extract all pictures' 160-d features, then I need to calculate cos distance between new face(validation data chosen from the same data set with training data set) and all pictures' 160-d features? Cause in training data, every people has more than 1 face picture.
So which way should I use?
A. calculate cos distance between new face and all training data,then choose a closest one as result.
B. average every people's 160-d feature,then calculate cos distance between new face and every people,then choose a closest one as result.

Thanks.