英语非谓语选择题The University of XXX still cotinues to exist,______

英语非谓语选择题
The University of XXX still cotinues to exist,_______into a modern university in 1947.
A being transformed B to be transformed C transformed D transforming
答案选的是C 我选的是A
我想问为什么A不行呢~一定要看成是非限制性which is
不知道是不是非限制性定语从句
有个句子 XXX has become selling tickets online for international flights,_______ to cut the market share ,,,,,,这里是填aiming 主动，那为什么刚才那个不能填A(被动