A body is projected vertically upwards from the surface of earth with a velocity equal to one third of escape velocity. The maximum height attained by the body will be\\
(Take radius of earth $= 6400 \mathrm{~km}$ and $g = 10 \mathrm{~ms}^{-2}$)\\
(1) 800 km\\
(2) 1600 km\\
(3) 2133 km\\
(4) 4800 km