Dr Dashing, the young and handsome general practitioner, mentions to his patient Carla that he is going to buy himself a new BMW as soon as he is able to sell his present car for a good price. Carla explains that she is looking to buy a second-hand car herself, and agrees to buy Dashing's car for $35,000. They arrange to meet in two days time to exchange the car and a bank cheque. The next day, Carla is told by her father that $35,000 is an excessive price to pay for the car. Carla is no longer wishes to proceed with the transaction.

On what grounds, if any, could Carla avoid liability?