I would say D, because you need to start with nothing to measure the different sizes as they start to grow. hope this helps!
Answer: The reaction is exothermic reaction as the energy of products is less than the energy of reactants.
Explanation: Exothermic reactions are defined as the reactions in which energy of the product is less than the energy of the reactants. The total energy is released in the form of heat and
for the reaction comes out to be negative.
Labeling of the parts in the diagram:
A represents the activation energy which is the energy required by reactants to cross the energy barrier to get converted to products.
E represents the potential energy of the reactants.
B represents the activated complex.
D represents the potential energy of the products.
C represents the total enthalpy change of the reaction, which comes out to be negative for exothermic reactions.

Greater absolute charge
- This is because ionic bond results from stronger electrostatic forces of attraction.
- The higher the value of charges q₁ and q₂ the stronger will be the ionic bond.