Activities of three radioactive substances $$A$$, $$B$$ and $$C$$ are represented by the curves $$A$$, $$B$$ and $$C$$, in the figure. Then their half-lives $$T_{1/2}(A) : T_{1/2}(B) : T_{1/2}(C)$$ are in the ratio:

A

$$2 : 1 : 1$$

B

$$3 : 2 : 1$$

C

$$2 : 1 : 3$$

D

$$4 : 3 : 1$$