Answer:
A. the speed of a reaction
Explanation:
The thermodynamic aspect of a reaction will show you the energy needed for a reaction to occur. If the energy difference(ΔG) is positive, which means the reaction is absorbing energy and it called endothermically. The opposite will be an exothermic reaction that will release energy, which means it doesn't need energy and the energy difference (ΔG) will be negative.
Thermodynamic can be used to determine a few things of a reaction, like the direction of the reaction, the extent, or temperature in which the reaction is spontaneous. But thermodynamic not used to find the speed of a reaction.