JEE Math Practice Question

A helicopter is flying along the curve given by y – x3/2 = 7, (x $$ \ge $$ 0). A soldier positioned at the point $$\left( {{1 \over 2},7} \right)$$ wants to shoot down the helicopter when it is nearest to him. Then this nearest distance is -

1. A.$${1 \over 6}\sqrt {{7 \over 3}} $$
2. B.$${{\sqrt 5 } \over 6}$$
3. C.$${1 \over 2}$$
4. D.$${1 \over 3}$$$$\sqrt {{7 \over 3}} $$