Mary's Little Lamb Restaurant hires David to purchase a piect of property so that Mary can build a new restaurant specializing in Middle Eastern cuisine. After negotiations are complete, David emails Mary, asking for a copy of the company's financial statements, which are necessary to close the deal. David gets no response, and a week later the property is sold to someone else. Mary is furious. Which of the following statement is true?

a$.$ David has breached his duty against self$-$dealing.

b$.$ Mary has breached her duty to compensate.

C$.$ Mary has breached her duty to assist with the agent's tasks.

d$.$ David has breached his duty of loyalty.