关于一道英语题中逗号的问题
After the meeting＿＿＿＿＿＿＿＿＿the different teams tried to construct a bridge over the river.
A ,and following the instructions we’d been given
B ,and following the instructions we’d been given,
C and following the instructions we’d been given,
D and following the instructions we’d been given
正确答案选b,但是为什么啊?
是插入语我懂了，可是如果选c，即After the meeting and following the instructions we’d been given，
the different teams tried to construct a bridge over the river。有什么错误啊？