C & B are switched so I'm not sure if that was a typo or not, but the answer is concentration!
The answer is (3) HClO. In the Cl2, chlorine has an oxidation number of zero. In HCl, the oxidation number is -1. In HClO2, the oxidation number is +3. In HClO, it is +1. You can calculate this by using O with oxidation number of -2 and H with +1.
Marie Curie discovered polonium and radium. Hope this helps:))) Please, mark Brainliest!
Physical change because ther is force which is the electric current
