Which of the Following Statements Regarding the Use of Radionuclides $\gamma$

Which of the following statements regarding the use of radionuclides for diagnostic purposes is NOT correct?

A) The half-life of the radionuclide should be as long as possible in order to maximize detection.
B) The radionuclide should be a moderate-energy $\gamma$ emitter.
C) The radionuclide should accumulate in the tissue or organ under study.
D) Trace amounts of the radionuclide are used along with much larger amounts of the stable isotope.
E) Different isotopes are used for different applications.