D obtained a loan of P100,000 from . The debt which is payable in 10 equal monthly installments is secured by a real mortgage on D's lot. David paid the first installment of P10,000 on due date. T, a third person, paid C P100,000 without the knowledge of D and believing that the amount owed by D was still P100,000. Which is correct?

a.

T can recover P90,000 from D. If David cannot pay, Theodore cannot foreclose the mortgage.

b.

T cannot recover any amount from D. Neither can he foreclose the mortgage because he paid C without the knowledge of D.

c.

T can recover P100,000 from D. If cannot pay, Theodore can foreclose the mortgage.

d.

T can recover P90,000 from D. If D cannot pay, Theodore can foreclose the mortgage.