As part of the initial investment, a partner contributes equipment that had originally cost $$80,000$ and on which accumulated depreciation of $$50,000$ has been recorded. If the partners agree on a valuation of $$50,000$ for the contributed equipment, what amount should be debited to the equipment account?

a$.$ The equipment's original cost

b$.$ The difference between the equipment's original cost and the valuation as agreed upon by the partners

c$.$ The equipment's valuation as agreed upon by the partners

d$.$ None of these choices are correct.