Answer

A-q,s ; B-p,q,r,s ; C-p,q,r,s ; D-q,s

Explanation

Alpha particle moving in electric field of nucleus is under central force and its mechanical energy is also conserved. Thus, `A to` (q,8s)
For electron moving in Bohr.s orbit:
K.E.=-T.E.
Also, T.E.=`1/2`P.E.
the motion of electron is also under central force and mechanical energy conservation is also applicable.
B `to` (p,q,r,s)
For motion of the Moon around the Earth
K.E.=-T.E.
`therefore` P.E.=2T.E.
Also motion of the Moon around the Earth is under the central force and mechanical energy is also conserved.
Thus , C `to` (p,q,r,s)
For free fall in vacuum, the mechanical energy is conserved and the object falls towards the centre of the Earth under central force.
D `to` (q,s)