Let $S ( \alpha ) = \{ ( x , y ) : y ^ { 2 } \leq x , 0 \leq x \leq \alpha \}$ and $A ( \alpha )$ is area of the region $S ( \alpha )$. If for a $\lambda$, $0 < \lambda < 4$, $A ( \lambda ) : A ( 4 ) = 2 : 5$, then $\lambda$ equals:\\
(1) $4 \left( \frac { 2 } { 5 } \right) ^ { \frac { 1 } { 3 } }$\\
(2) $2 \left( \frac { 4 } { 25 } \right) ^ { \frac { 1 } { 3 } }$\\
(3) $4 \left( \frac { 4 } { 25 } \right) ^ { \frac { 1 } { 3 } }$\\
(4) $2 \left( \frac { 2 } { 5 } \right)$