Answer:
Kantian ethics.
Step-by-step explanation:
Kantian ethics is a deontological moral theory founded on Kant's theory. According to this theory, the right or wrong actions doing does not rely upon the consequences but whether or not they carry out their duty.
In the given case, Mary's decision is in accordance with Kantian ethics as she decides to pay her suppliers on time.
Therefore, Kantian ethics is the correct answer.