A and B formed a partnership, with A as managing partner. X owes B P10,000.00 payable on February 20, 2020. X is also indebted to the partnership in the amount of P20,000.00 payable on February 20, 2020. On February 20, 2020, X paid B P10,000.00, the latter issuing a receipt of his own. In this case -*

a. The P10,000.00 shall be applied to the debt of X to the partnership.

b. The P10,000.00 shall be applied equally to both debts of X to the partnership and B.

c. The P10,000.00 shall be applied proportionately to both debts of X to the partnership and B.

d. The P10,000.00 shall be applied to the debt of X to B.