Donna pledged a set of diamond ring and earrings to Jane for P200,000.00 She was made to sign an agreement that if she cannot pay her debt within six months, Jane could immediately appropriate the jewelry for herself. After six months, Donna failed to pay. Jane then displayed the earrings and ring set in her jewelry shop located in a mall. A buyer, Juana, bought the jewelry set for P300,000.00. a) Was the agreement which Donna signed with Jane valid? Explain with legal basis. (2%) b) Can Donna redeem the jewelry set from Juana by paying the amount she owed Jane to Juana? Explain with legal basis. (2%) c) Give an example of a pledge created by operation of law. (2%)