Hai is the general director of a company that manages bookings for a traditional dancing act that performs throughout Vietnam. He manages contracts with customers, as well as the administration arrangements for the act’s appearances, including hotels and travel.Hai concluded a contract with a concert organiser in Ho Chi Minh City. The contract specified the fee to be paid for the dancing act to appear, and a fixed sum to cover accommodation and travel from Hanoi. Three weeks before the concert in Ho Chi Minh City, Hai decided to organise flights for the performers but discovered that due to a fuel crisis the fares for the flights would be 60% more expensive than originally estimated. Hai decided to withdraw from the contract as he did not wish to incur a loss.Hai concluded a similar contract with a concert organiser in Da Nang. On the morning of the day on which the concert was planned to take place, the theatre was seriously damaged by fire, causing the cancellation of the concert by the organiser. The dancing act had already travelled to Da Nang and had paid for all travel and accommodation necessary for its appearance. Hai decided to invoice the organiser for the full fee and expenses incurred.Required:

(b) Discuss the potential liability of the concert organiser in Da Nang for the fees and expenses invoiced by Hai’s company. (5 marks)

物业服务合同通常在( )时即生效。

A．成立

B．签订

C．协商

D．执行