A borrowed P100,000 from B and mortgaged his house to secure the payment of the loan. T contract of real estate mortgage is not notarized and not registered with Registry of Deeds. T contract of real estate mortgage provides that A is prohibited from selling the mortgaged hou in case of default of A at the maturity date of the loan, B will become the automatic owner of mortgaged house. Which of the following statements is correct? A. A may still sell the house to third person despite the prohibition in the contract of re estate mortgage. B. B becomes the owner of the mortgaged house upon default of A. C. The contract of real estate mortgage is null and void because of the stipulation of pactum commissorium which is contrary to law and public policy. D. The contract of real estate mortgage is unenforceable because it is not in public documen not registered with Registry of Deeds