The amount of radioactive material in a sample decreases by 50% every day. The sample started with 120 milligrams of radioactive material. A scientist wants to find the length of time in days, t, until the sample contains less than 3 milligrams of radioactive material. Which inequality can the scientist use to find t?
a. 120-0.5t≤ 3
b. 120(0.5)ᵗ<3
c. 120(-0.5)ᵗ<3
d. 120(0.5)^²ᵗ<3
e. 60<3ᵗ
f. 120(0.5)ᵗ>3