Need help with chemistry please need to pass?

It is A. Electron clouds. Planetary and stick figures aren't even atom models. The solid spheres was upadated by the plum pudding, and was passed by the actual: electron clouds. This model states that it is impossible to know to a given time, the position of an electron. So it is all about probability of finding an electron. The thicker the area, the most likely it is to find an electron in the area.