The correct option is B Dynamic equilibrium can be established in open as well as closed containers.
Option (d) is false as Dynamic Equilibrium can only be achieved in a closed container. In an open container, the reaction in one direction will always take precedence over reaction in the other direction. An example is evaporation of water. As water molecules continue to escape into the air in an open container, the system will never be able to achieve a state of equilibrium.