¹³¹I Has a Half-Life of 8

Multiple Choice

¹³¹I has a half-life of 8.04 days. Assuming you start with a 1.03 mg sample of ¹³¹I, how many mg will remain after 13.0 days?

A) 0.326
B) 0.268
C) 0.422
D) 0.0781
E) 0.336