Most importantly?most important?

问题描述:

Most importantly?most important?
Most___,don't pollute the water.
Most importantly 是正确答案,但我不知道为什么要填importantly,
A.important B.importantly C.importance D.importances
importantly是adv.副词喔.

应该是最重要的是.
和luckily类比
应该是可以加LY的
翻译成(最重要的是).