A radioactive isotope has an initial activity ${A_0}$ and a half-life of 1 day. The graph shows how the activity $A$ varies with time.

The ratio $\frac{{{A_0}}}{{{A_2}}}$ is equal to which of the following?

A.     $\frac{{{A_1}}}{{{A_3}}}$

B.     $\frac{{{A_0}}}{{{A_3}}}$

C.     $\frac{{{A_0}}}{2}$

D.     $\frac{{{A_3}}}{3}$

A

The diagram was not drawn strictly to scale, but this did not confuse the majority of the students.