Which of the following would speed up a chemical reaction in aqueous reaction

The answer to the first is "Reactants collide to form a transition state." - The products of a reaction are what is formed; it is the reactants that collide. 

The answer to the second is "adding more powdered reactants" - Adding excess cold water would cool the mixture down, thus supplying less kinetic energy to the molecules causing less energetic collisions, and also dilutes the reactants; decreasing the concentration, which would decrease the number of collisions per second, thus decreasing the rate of reaction. If you add more powdered reactants however, this would increase the reactant concentration, and thus increase the number of collisions per second. 

The answer to the third is "increasing the concentration of reactants" and "decreasing the concentration of products" because these both increase the concentration of the reactant molecules in the solution, increasing the chance that they will collide and react to form product. Therefore increasing the rate of reaction without giving any energy (which would be via heat or pressure) 

The others I wouldn't be 100% on.