Rank the Following Types of Radiation from Least Penetrating to Most

Rank the following types of radiation from least penetrating to most penetrating: $\alpha$ , $\beta$ or $\gamma$

A) ( $\alpha$ < $\beta$ < $\gamma$ )
B) ( $\beta$ < $\gamma$ < $\alpha$ )
C) ( $\gamma$ < $\beta$ < $\alpha$ )
D) ( $\alpha$ < $\gamma$ < $\beta$ < )
E) ( $\beta$ < $\alpha$ < $\gamma$ )