Because of continuing financial constraints, XYZ, Inc. gave its employees the option to voluntarily resign from the company. A was one of those who availed of the option. On October 5, 2007, he was paid separation benefits equivalent to seven (7) months pay for his six (6) years and seven (7) months of service with the company and he executed a waiver and quitclaim. A week later, A filed against XYZ, Inc. a complaint for illegal dismissal. While he admitted that he was not forced to sign the quitclaim, he contended that he agreed to tender his voluntary resignation on the belief that XYZ, Inc. was closing down its business. XYZ, Inc., however, continued its business under a different company name, he claimed. Rule on whether the quitclaim executed by A is valid or not. Explain. (3%)