A) how will increasing the concentration of co shift the equilibrium?

Since there is no equation provided, I will tell you the concept of equilibrium and you apply it on your equation.

Equilibrium occurs when the rate of the forward reaction is equal to the rate of the reverse reaction.

1 - If you increase the concentration of one or more of the reactants: The rate of forward reaction will increase over that of the reverse reaction in order to form more products and balance the concentrations to reach equilibrium again. The equilibrium will shift to the right.

2 - If you increase the concentration of one or more of the products: The rate of the reverse reaction will increase over that of the forward reaction in order form more reactants and balance the concentrations to reach equilibrium again. The equilibrium will shift to the left.