An Initial Amount of 300 G of the Radioactive Isotope

An initial amount of 300 g of the radioactive isotope thorium-234 decays according to , where t is in years. How long does it take for half of the initial amount to disintegrate? This time is called the half-life of this isotope. Round your answer to one decimal place. ​

A) 240.5 years
B) 170.7 years
C) 24.5 years
D) 27.5 years
E) 245.1 years