at the end of party,______of thegirls was given a small gifta every b each

at the end of party,______of thegirls was given a small gift
a every b each

很高兴能够在这里回答你的问题,应该为：
B
every后面不跟of
each of 每一个

a
party嘛，人必然多于3个，多个人中的每一个，用every