Maufacturing is Canada’s most important economic activity, _
Maufacturing is Canada’s most important economic activity, ____17 percent of the workforce.
(A) engages
(B) and to engage
(C) that it engage
(D) Engaging
这题为什么选择D,我刚开始想选择c 但是C得错误是engage应该为engages是吗?请详细解答