Consider the reaction.

2so2(g)+o2(g) < > 2so3(g)

when does the given chemical system reach dynamic equilibrium?
when the forward and reverse reactions stop
when the rate of the forward reaction is higher than the rate of the reverse reaction
when the concentration of the reactants is higher than the concentration of the products
when the rates of the forward and reverse reactions are equal

when the rates of the forward and reverse reactions are equal

Explanation:

Dynamic Equilibrium :  It is a reaction which never stops. But in this type of equilibrium concentration of products and reactants doesn't get alter with the time.The rate of reaction going in a forward direction is equal to the rate of reaction going in a backward direction.

Hence, the given chemical system reach dynamic equilibrium when the rates of the forward and reverse reactions are equal

it's filtration, but this is an assumption so my apologies if i got this