A certain radioactive material loses (1)/(10) of its mass in 6 hours. What is the half-life of the material?

A) t=(-6ln2)/(ln((9)/(10)))
B) t=(6ln2)/(ln((9)/(10)))
C) t=(ln((9)/(10)))/(-6ln2)
D) t=(ln((9)/(10)))/(6ln2)