Answer: C. I look forward to working with a woman doctor soon.
Bias refers to an unfair prejudice a person has towards a particular group, person or thing. In this sentence, the author is showing a gender bias, as he prefers to work with women than with men. Whether that is a "positive" stereotype (women are more capable, they work harder, etc.) or a negative one (women are more attractive, easier to control, etc.), it gives an unfair advantage to one gender over the other one with no fair justification. Therefore, it is to be discouraged in the workplace.