Final answer:
The worst possible action when faced with an ethical dilemma is to do nothing and ignore the situation.
Step-by-step explanation:
In ethical dilemmas, the worst possible action to take is to do nothing and ignore the situation (c). This is because ignoring the situation means not addressing the ethical issue at hand and potentially allowing harm to continue. Seeking guidance from superiors (a), choosing the course of action with the least harm (b), or consulting with peers for advice (d) are all better approaches to ethical dilemmas as they involve actively addressing the situation and considering the potential consequences of different actions.