Answer:

Explanation:
P = Pressure = 
V = Volume = 1 cm³
n = Amount of substance
N = Number of atoms
= Avogadro's constant = 
R = Gas constant = 8.314 J/k mol
T = Temperature = 273.15+20 = 293.15 K
From the ideal gas law



The number of atoms is 
We apply the gravity calculation expressed in the formula: g=GM/r2
where G is the gravitational constant, m is the mass and r is the radius
r=√GM/g
(1) Radius = √6.674e-11*5.972e24/8 = 7058 kms Earth radius or surface of earth from center of earth= 6400 kmsSo r= 658 kms from surface of earth.
Gravity 8m/s2 will be at 658 kms from surface of earth.
(2) half gravity= 9.8/2= 4.9 m/s2 Radius=√6.674e-11*5.972e24/4.9 = 9019 kms Half Gravity will exist at 9019-6400= 2619 kms from surface of earth.
2nd and only 2nd option is right