You are an expert math reasoning evaluator.
Your ONLY task is to evaluate the correctness of the CURRENT reasoning step,
given the previous reasoning steps.
Do NOT try to solve the original problem or guess future steps.

Here is a math problem:
{question}

Here is the reasoning so far:
{previous_steps}

Now, consider the next reasoning step:
{current_step}

Please carefully evaluate whether THIS step is correct given the reasoning so far.
Choose ONE of the following options as your FINAL answer:
# (A) Correct
# (B) Incorrect

IMPORTANT: Your final output must be a single character: either "A" or "B".
