Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

With regard to the net present value (NPV) profiles of two projects, the cross-over rate is best described as the discount rate at which:
Option A:two projects have the same NPV.
Option B:two projects have the same internal rate of return.
Option C:a project’s NPV changes from positive to negative.

Answer: A