Answer:The correct answer is option A.
Step-by-step explanation:
Reaction rate: It is defined as speed at which the reaction takes place or speed at which reactants are getting converted into products.It is the change in the concentration of any of the reactants or products per unit time.
Activation energy is defined as the minimum amount of energy required by the reactants to undergo specified reaction.
Meta stable state is defined as state of an atom or nucleus with the longer life time in other excited states.
Spontaneous reaction are defined as those reaction which do not require any external force or effort to occur.
From all the definition stated above the , the correct answer of the asked question is option A.