Two cones A and B have equal slant heights. The sum of the central angles of their lateral surface development diagrams is $2 \pi$. Let their lateral surface areas be $S_{\text{甲}}$ and $S_{\text{乙}}$, and their volumes be $V_{\text{甲}}$ and $V_{\text{乙}}$. If $\frac { S_{\text{甲}} } { S_{\text{乙}} } = 2$ , then $\frac { V_{\text{甲}} } { V_{\text{乙}} } =$\\
A. $\sqrt { 5 }$\\
B. $2 \sqrt { 2 }$\\
C. $\sqrt { 10 }$\\
D. $\frac { 5 \sqrt { 10 } } { 4 }$