Answer: a. Reasonable skill and care and obedience
Step-by-step explanation:
The Fiduciary responsibility of Reasonable Skill and Care charges that professionals in a contract should give the same level of skill and care that another competent member of the profession will be able to give. Essentially, Professionals should do their best in a contract to execute it. Marla needs to exercise this fiduciary responsibility by listing Tristan's property on the MLS so that it is sold faster.
However, this will go against her other Fiduciary Responsibility to Tristan, that of Obedience. Tristan's wishes as the client are supposed to be listened and adhered to. Marla is supposed to follow Tristan's directives and remain faithful to them. His directive in this scenario is that Marla does not register the property on the MLS and Marla needs to follow this.
The two fiduciary duties are at odds in this situation are therefore those of Reasonable skill and care and Obedience.