请问老师B错在哪里。

问题如下：

Question The change in polarity principle most likely helps analysts determine a new:

选项：

A.support level after a retracement to a lower high than a previous retracement. B.resistance level after an upward breakthrough of the trendline. C.support level after a resistance level is breached.

解释：

Solution

C is correct. A key tenet of support and resistance levels in technical analysis is the change in polarity principle, which states that once a support level is breached, it becomes a resistance level. The same holds true for resistance levels: once breached, they become support levels.

A is incorrect. The change in polarity principle states that once a support level is breached, it becomes a resistance level; it does not help determine a new support level during an ongoing downtrend.

B is incorrect. The change in polarity principle states that once a resistance level is breached, it becomes a support level; it does not help determine a new resistance level during an ongoing upward trend.