On an ECG tracing, what is an isoelectric line called?

The chief complaint is defined as:

a. an evaluation of the patient's vital signs. b. the cause of the patient's current symptoms. c. a list of symptoms as stated by the patient. d. the reason/problem for which the patient sought treatment.

Which of these patients should the EMT recognize as tachycardic for his or her age bracket?

A) An 86-year-old male with chest pain and a heart rate of 96 B) A 2-year-old female with vomiting and a heart rate of 116 C) A 24-year-old female with diabetic complications and a heart rate of 54 D) A 37-year-old male with a complaint of fatigue and a heart rate of 104