A projectile is fired vertically upwards from the surface of the earth with a velocity kvₑ where vₑ is the escape velocity and k<1. If R is the radius of the earth, the maximum height to which it will rise measured from the centre of earth will be (neglect air resistance)

A. 1−k²/R
B. R(1−k²)
C. R/1−k²
D. R/1+k²