The managers discussed the plan that they would like to see

see sth done carry out是实施（计划）的意思变成被动,选c 分析一下句子的语法结构：that they would like to see ___ the next year是定语从句,先行词为plan,在定语从句中由that代替,see sth（that） done（carried out）这里面done是做宾语补足语。