Three equal mass satellites $A, B,$ and $C$ are in coplanar orbits around a planet as shown in the figure. The magnitudes of the angular momenta of the satellites as measured about the planet are $L_A, L_B$,and $L_C$. Which of the following statements is correct?

$A$ satellite is to be placed in an equatorial geostationary orbit around the Earth for communication.
$(a)$ Calculate the height of such a satellite.
$(b)$ Find out the minimum number of satellites that are needed to cover the entire Earth,so that at least one satellite is visible from any point on the equator.
Given: $M = 6 \times 10^{24} \ kg$,$R = 6400 \ km$,$T = 24 \ h$,$G = 6.67 \times 10^{-11} \ N \cdot m^2/kg^2$.

Two satellites of equal mass are revolving around Earth in elliptical orbits of different semi-major axes. If their angular momenta about the Earth's center are in the ratio $3:4$,then the ratio of their areal velocities is ........

The kinetic energy of a revolving satellite of mass $m$ at a height equal to thrice the radius of the Earth $R$ is:

In a satellite,if the time of revolution is $T$,then the kinetic energy $(K.E.)$ is proportional to:

The distances of two planets $A$ and $B$ from the sun are $r_A$ and $r_B$ respectively, such that $r_B = 100 r_A$. The ratio of the orbital speed of planet $A$ to that of planet $B$ is (both planets are revolving around the sun in circular orbits).