Rita Is Appointed as an Agent for Superior Sales,Inc

Rita is appointed as an agent for Superior Sales,Inc.The agency agree?ment is silent as to the level of sales that Rita is expected to achieve.She must

A) achieve nothing because the agreement says nothing on the issue.
B) attain the level that Rita achieved with her previous employer.
C) maintain the level Superior attained before Rita became an agent.
D) use reasonable diligence and skill in selling.