Project A requires an immediate investment of $$18000$ and another $$16000$ in three years. Net returns are $$4500$ after two years, $$13000$ after four years, and $$8900$ after six years. Project B requires an immediate investment of $$4000,$ another $$6000$ after two years, and $$4000$ after four years. Net returns are $$3375$ per year for $8$ years. Determine the net present value at $11\%.$ Which project is preferable according to the net present value criterion?