10.2 hours is equivalent to three half-lives, so after 10.2 hours, the mass of the sample would have decayed by half three times over. If one starts with 100 mg of the sample, then after three half-lives, there would be 100(0.5)³ = 12.5 mg of the sample remaining.
Thus, the correct answer choice here would be D.
Explanation is in the file
tinyurl.com/wtjfavyw
They must have the same rights to become a citizen as someone born in the U.S
