Oh,what a pity!It________ so easy for me to bring those photographs.I wanted to show you,but I’ve left them at the table

Oh,what a pity!It________ so easy for me to bring those photographs.I wanted to show you,but I’ve left them at the table at home.
A.would have been B.would be
C.had been D.was
为什么 给的是A
如果是虚拟语气的话 它属于什么情况的虚拟语气呢？比如有IF引导的虚拟语气或者是其他原因引起的虚拟语气？