Answer the questions first by YES or NO, indicate the article then explain or state the rule or reason for your answers briefly. 1. X borrowed Php50,000 from Y payable on or before September 30, 2021. Before the arrival of the due date, X agreed to Y's promise to pay Y if X wants. Can Y demand X to pay not later than September 30, 2021?

2. X borrowed Php50,000 from Y at 12% interest per annum payable on December 31, 2021. Can X require Y to accept payment before December 31, 2021?

3. X borrowed Php50,000 from Y. It was agreed that X could pay Php50,000 or deliver his electric scooter on September 21, 2021. Can X still change this period?

4. A, B, and C (the debtors) bound themselves to pay D Php50,000. The debtors agreed that A will receive the entire Php50,000 from D. On the due date of the obligation, can D demand the full payment of Php50,000 from A alone?