一条关于独立主格结构的选择题

题目

一条关于独立主格结构的选择题
The largest collection ever found in England was one of about 2000000 silver pennies,_____ over 600 years old.
A all of them B.all of which C all of it D none of which
意思我知道,主要是语法上的疑问,独立主格也应该有个being吧?

答案

独立主格的一个构成是
主语+介词短语副词,即being可以省略
Class being over,the students soon left the classroom.
=Class over,the students soon left the classroom
同样,这题有没有being都是对的