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.

The “change in polarity” principle states which of the following?
Option A:Once an uptrend is broken, it becomes a downtrend.
Option B:Once a resistance level is breached, it becomes a support level.
Option C:The short-term moving average has crossed over the longer-term moving average.

Answer: B