A graph titled half-life graph of a radioactive isotope is shown with mass remaining on the y axis from 0 to 60 grams and time on the x axis from 0 to 6 minutes. A curve connects the points 0, 50 and 1, 25 and 2, 12.5 and 3, 6.25 and 4, 3.125 and 5, 1.5625. What is the mass of the radioactive isotope remaining at 2.0 minutes? A. 25.0 mg B. 12.5 mg C. 6.25 mg D. 3.13 mg