What letter represents the activation energy for the reverse reaction?

Answer : The letter represents the activation energy for the reverse reaction is, U.

Explanation :

Activation energy : It is defined as the minimum amount of energy given to the reactant so that it gets converted into products.

Or we can say that, It is the minimum amount of energy that is absorbed by the reactant molecules so that their energy becomes equal to the threshold energy.

The activation energy is represented as the energy from the reactants to the activated complex or transition state.

Reverse reaction : It is defined as the reaction in which the products become reactants and proceed to the formation of the reactants back.

From the given image we conclude that, the activation energy of the reverse reaction is the energy between the product (X) and the activated complex (W), that is represented as letter U.

Hence, the letter represents the activation energy for the reverse reaction is, U.

the answer would be c