Answer:
b. H-3
Explanation:
The half life of the following isotopes is given as;
a. 0-19
26.88 seconds
b. H-3
12 years
c. Zn-71
2.4 minutes
d. Rb-85
This is a stable isotope. It does not decomposes.
Comparing the half lives, the isotope with the longest half life is Hydrogen - 3. With half life of 12 years.
