Compass is at magnet, radio is at electric, socks at magnet, air filter at electricity
A.
Because you increase the concentration of the reactants, it means that there are more molecules of the reactants present in a smaller amount of space.
This being the case, there is a higher chance that these molecules will collide with enough energy to overcome the activation barrier.
The other ones are completely wrong, but if you would like an explanation as to why they are, just ask :)