Mr Ma and Ms Yang entered into a loan agreement and a security agreement, under which Mr Ma would provide his truck as the mortgage to Ms Yang for borrowing RMB 200,000 yuan. However, they failed to register the mortgage agreement. Several months later, Mr Ma borrowed another RMB 200,000 yuan from Mr Lee and delivered his truck as the pledge to Mr Lee. The two parties then registered the pledge agreement. Upon the expiration of the loan agreements, Mr Ma was unable to repay the capital and interest. A dispute occurred between Ms Yang and Mr Lee, since they intended to exercise the right of guarantee simultaneously. Required: In accordance with the Property Law of China: (a) Explain whether the mortgage agreement between Mr Ma and Ms Yang came into effect. (2 marks) (b) Describe when the right of pledge between Mr Ma and Mr Lee was established. (2 marks) (c) Explain who should be repaid in priority if the truck was auctioned. (2 marks)