The correct option is B The rate at which a reaction proceeds.
Thermodynamics does not tell us about the rate of the reaction. It is not concerned about how and at what rate energy transformation is carried out.
Chemical kinetics tells us about the rate of reaction and factors affecting rate of chemical reaction.
Thermodynamics is the branch that deals with the transformation of energy from one form to another.
It also gives an idea about whether a reaction will be going to take place or not and it also gives an idea about the extent of the reaction.