Two identical samples of a tracer with a half-life of 10min are prepared. Sample A is monitored until 12.5% of its original nuclei remain, whereas Sample B is monitored until 6.25% remain. Which statement correctly compares their decay times?
a) Sample B decays for twice as long as Sample A.
b) Sample B decays for one additional half-life beyond the time for Sample A.
c) The decay times are the same because both depend only on the half-life.
d) Sample B decays for 25% longer than Sample A.