A Freshly Prepared Sample of Curium-243 Undergoes 3312 Disintegrations Per $\text { half-life }$

A freshly prepared sample of curium-243 undergoes 3312 disintegrations per second.After 2.00 y.,the activity of the sample declines to 3115 disintegrations per second.The $\text { half-life }$ of $\text { curium-243 }$ is ---------- $\text { y. }$

A) 0.157
B) 2.13
C) 32.6
D) 1.88
E) 22.6