The legal profession conducted a study to determine the percentage of cardiologists who had been sued for malpractice in the last six years. The sample was randomly chosen from a national directory of doctors. Identify the individuals in the study. A) the doctor's area of expertise (i. e, cardiology, pediatrics, etc.) B) the responses: have been sued/have not been sued for malpractice in the last live years C) all cardiologists in the directory D) each cardiologist selected from the directory