Classify the actions based on how they could affect a reaction rate

1) Decrease the surface area of solid reactant - It will decrease the rate as the surface area available of collision of particles will be decreased.

2) Add a catalyst - Adding catalyst increases the rate as catalyst decreases the activation energy and hence number of particle for collision increases

3) Increase in temperature - Increase in temperature increases the rate as increment in temperature will.increase the energy of particles.

4) Decrease the concentration of reactants - It will decrease the rate of reaction as the number of available particles for collision decreases.