I am unable to figure this out problem. I need help

A certain group of test subjects had pulse rates with a mean of 83.1 beats per minute and a standard deviation of 12.4 beats per minute. Use the range rule of thumb to identify the limits separating values that are significantly low or significantly high. Is a pulse rate of 97.9 beats per minute significantly low or significantly high? Significantly low values are beats per minute or lower. (Type an integer or a decimal. Do not round.) Significantly high values are beats per minute or higher. (Type an integer or a decimal. Do not round.) Is a pulse rate of 97.9 beats per minute significantly low or significantly high? O A. Neither, because it is within two standard deviations of the mean. O B. Significantly low, because it is more than two standard deviations below the mean. O C. Significantly high, because it is more than two standard deviations above the mean. O D. It is impossible to determine with the information given