A student heard a sports news report that several fans who were wearing smartwatches received irregular heart rate warnings as they were viewing the last few minutes of a football playoff game. What could be the possible reason for this?
A) The fans were too excited and their heart rates increased.
B) The smartwatches were malfunctioning and giving false warnings.
C) The football game was very intense and caused stress to the fans.
D) The smartwatches were accurately detecting irregular heart rates.