Which has the largest rate constant, K? A. Skin tanning in the sunshine
B. Dynamite exploding
C. Copper statues turning green
D. Chemical changes causing leaves to brown in the fall

B. Dynamite exploding

Explanation:

A large K implies that most of the reactants are converted to products at equilibrium. It implies that the reaction mostly proceed to the right with a substantial amount of product at equilibrium. Hence the reaction tends towards the right-hand side.

Dynamite exploding is a combustion reaction. Remember that a combustion reaction will have a larger value of K than all other processes listed in the question.