请大家帮帮忙three months later,the hostages were more dead than alive

请大家帮帮忙three months later,the hostages were more dead than alive
______________three months later,the hostages were more dead than alive.
A.Having rescued B.Rescuing
C.Having been rescued D.Rescued
这道四选一我怎么选都是C,为什么正确答案是D呢?有何语法依据?
10) _______,shanghai is probably the best place for the next Asian Games.
A.Considering all things B.All things being considered
C.All things considered D.To consider all things
请问这道题为什么是独立主格,为什么不能选择A选项?是怎么考虑出来的呢?