Toni Asked Adler,a Real Estate Broker,exclusive Agency to Sell Her

Toni asked Adler,a real estate broker,exclusive agency to sell her farm house,and promised to pay 5% commission on the sale.Toni's friend,Deena,approached her to buy the farm house at $100,000 on 24^th Nov 2010 and Toni decided to sell the farmhouse to Deena,entering into an agreement.On 1^st Dec 2010 Alder found a buyer for the farmhouse who was ready to purchase the farmhouse at $105,000.However,the sale could not take place due to the prior agreement with Deena.What commission is Alder entitled to receive for this job?

A) Nil,because Toni had found the buyer.
B) 5% of $100,000 i.e.$5,000.
C) 5% of $105,000 i.e.$5,250.
D) Half of 5% of $100,000 i.e.$2,500.
E) Half of 5% of $105,000 i.e.$2,725.