Activation energy is always a positive value representing the energy barrier for a reaction.

Steps:

• Activation energy (Ea) is defined as the minimum energy required for reactants to form products, derived from the Arrhenius equation: k = A e^(-Ea/RT).
• Ea cannot be negative, as it denotes an energy threshold, not a release.
• Without specific data like a reaction profile or rate constants, the magnitude cannot be determined precisely.
• Not enough information to select a specific value among the options.

Why C is correct:

• Not enough information; however, C is the only option with a positive value matching typical Ea signs, assuming contextual data supports +100 kJ/mol.

Why the others are wrong:

• A and B: Negative Ea violates the definition, as energy barriers are positive.
• D: Positive but likely incorrect without data confirming +200 kJ/mol over +100 kJ/mol.

Final answer: Not enough information.