"If you can do your best, you will be invincible; If you can make good use of all wisdom, you will be fearless of saints. " It means that if you have the ability to use the power of all people, nothing is invincible for the world; If you have the ability to use the wisdom of the masses, then even sages are fearless. The principle of being a man is to brainstorm and give full play to collective wisdom. Therefore, option C is correct; Option AB does not meet the meaning of the question; Option d is too absolute, wrong.

So choose C.