Which researcher or group of researchers labeled protein and DNA with different isotopes to determine which was the genetic material? Pick the best answer. Select one: a. James Watson and Francis Crick b. Barbara McClintock c. Maurice Wilkins and Rosalind Franklin d. Phoebus Levene e. Heinz Fraenkel-Conrat and Bea Singer f. Alfred Hershey and Martha Chase g. Erwin Chargaff h. Oswald Avery, Colin MacLeod and Maclyn McCarty i. Frederick Griffith j. Albrecht Kossel k. Friedrich Miescher I. Charles Yanofsky.