I only have $5.00 left and I hope that's enough to answer this question. Each of the following nuclides is used in nuclear medicine.

I only have $5.00 left and I hope that's enough to answer this question.  Each of the following nuclides is used in nuclear medicine.  List them in order of most active (largest number of decay events per second) to least active (smallest number of decay events per second).  

Nuclides                           Half-Life

P-32                                   14.3 days

Cr-31                                  27.7 days

Ga-67                                 78.3 hours      

Sr-89                                  50.5 days