Just before a reversible reaction attains equilibrium it is found that

Explanation

Option B is correct.The velocity of the forward reaction is decreasing and that of the backward reaction is increasing.In a reversible reaction, the forward reaction is the reaction that goes from reactants to products. The backward reaction is the reaction that goes from products to reactants.At equilibrium, the rates of the forward and backward reactions are equal. This means that the amount of reactants and products being produced is equal.Just before equilibrium is reached, the rate of the forward reaction is decreasing. This is because the concentration of reactants is decreasing. The rate of the backward reaction is increasing. This is because the concentration of products is increasing. As the reaction proceeds, the concentrations of reactants and products continue to change. The rate of the forward reaction continues to decrease, and the rate of the backward reaction continues to increase. Eventually, the rates of the forward and backward reactions become equal, and equilibrium is reached.