Answer: option B, Equilibrium
Explanation: Formation of ester by the reaction of Carboxylic acid and alcohol in the presence of mineral acids is called Esterification.
And entire reaction is a reversible and in equilibrium
A reverse reaction occurs on hydrolysis of Ester.
Hence Reactants and products are in equilibrium.
Example
CH3COOH+C2H5OH <------> CH3COOC2H5 +H2O