Select the correct choice$(s)$:

• A
  The gravitational field inside a spherical cavity,within a spherical planet,must be non-zero and uniform.
• B
  When a body is projected horizontally at an appreciably large height above the earth,with a velocity less than that required for a circular orbit,it will fall to the earth along a parabolic path.
• C
  $A$ body of zero total mechanical energy placed in a gravitational field will escape the field.
• D
  Earth's satellite must be in the equatorial plane.