Answer:
D. freedom of conscience (limited)
Step-by-step explanation:
Freedom of conscience consists is having the right to form one's own ethical and moral views, independent of other's beliefs, and also having the right to act in a way that is coherent with those ethical and moral views.
Even if Portia is an employee, and is legally bound to her employer in many ways, she is not obliged to do something that goes against her ethical and moral rationales, whether at the workplace, or a event outside of the office like the barbeque. As a vegetarian, she has the right to be excused from the party, and exercise in that way, her freedom of conscience.