B, for some tools, the brush method of "mechanical rotating parts" can't prevent rust, and the paint of "mechanical rotating parts" can't be hung, so B is wrong;

C, the method of protecting the hull by sacrificing zinc blocks can prevent the iron of the hull from rusting, which belongs to the cathodic protection method of sacrificial anode, so c is correct;

D. Oiling, painting, electroplating Cr and other metals can prevent steel from rusting, so D is correct.

So choose B.