In the Absence of Air Resistance,the Least Speed with Which $\times$

Multiple Choice

In the absence of air resistance,the least speed with which a body must be projected vertically upward from Earth's surface (m_e = 5.99 $\times$ 10²⁴ kg, r_e = 6.37 $\times$ 10⁶ m) if it is to reach an altitude of 800 km is

A) ~1.39 $\times$ 10⁷ m/s
B) ~3.73 $\times$ 10³ m/s
C) ~1.57 $\times$ 10⁷ m/s
D) ~3.96 $\times$ 10³ m/s
E) None of these is correct.