Two positively charged particles ` X` and `Y` are initially far away from each other and at rest , `X` begins to move towards `Y` with some initial velocity. The total momentum and energy of the system are `p` and `E`.
A. If `Y` is fixed both `p` and `E` are conserved.
B. If `Y` is fixed `E` is conserved but not `p`
C. If both are free to move `p` is conserved but not `E`
D. If both are free, `E` conserved, but not `p`.
