Kabelo is sitting with a group of his friends outside a restaurant by the river. He says that he will give P2,000 to anyone who can swim across the river. Kabelo puts the amount of the money on the table to show the seriousness of his challenge. Modisa is not with Kabelo’s group but is sitting at the table next to Kabelo. He hears the promise but does not say anything. Suddenly a child falls into the water from the other side of the river. Modisa dives into the water and begins to swim to her rescue. As Modisa is approaching the child, Kabelo shouts out: ‘Don’t think you are going to get my P2,000 because I am withdrawing the offer!’ Modisa nonetheless rescues the child and climbs out onto the other side of the harbour.Required:Explain whether Modisa can claim the P2,000 from Kabelo under the law of contract. (10 marks)

把铁粉撒在放于一根磁棒上的纸上，由铁粉形成的图形叫作（）

A．磁场测量图；

B．磁强计；

C．磁图；

D．磁通计