When a reaction has reached equilibrium,

Question

the reaction stops.

reactants are coverted to products at the same rate thet the products are converted to reactants.

the concentrations of reactants and products change very slowly.

the concetntrations of the reactants and products are the same.

Answer 1

I believe you mean this to be a multiple choice question?  The answer is that they are converted back and forth at the same rate, giving the appearance of no change, though it does not stop.

Answer 2

Converted back and forth at the same rate. That's what I have understood equilibrium to mean: that when the forward reaction rate is equal to the reverse reaction rate, the reaction is at equilibrium.