the shop was closed down---a shooting that was believed to have injured weveral customers/ A having followed B followed C was followed D following

the shop was closed down---a shooting that was believed to have injured weveral customers/ A having followed B followed C was followed D following
the shop was closed down---a shooting that was believed to have injured weveral customers/
A having followed B followed C was followed D following

the shop was closed down---a shooting that was believed to have injured weveral customers/ A having followed B followed C was followed D following
分析：
the shop was closed down--following- a shooting
a shooting that was believed to have injured weveral customers

个人觉得 选c