In this task, you are given a question containing a blank (_) and two options. You should pick the best option to answer the question. Please answer with "A" or "B".

Let me give you an example: Katrina gave Christine a stuffed animal for their birthday, but _ already had this one. (A) Katrina (B) Christine
The answer to this example can be: B
Here is why: Since the blank is someone who received the gift and already had a stuffed animal, the answer must be "Christine".

OK. solve this:
Samantha failed on the test but Mary got very good marks because _ had been very lazy. (A) Samantha (B) Mary
Answer:
A