The correct option is A gets doubled
The kinetic energy of a moving body is given by:
KE=12mv2
where:
m - Mass of the body
v - Speed of the body.
If mass m is doubled, new mass is given by:
m′=2m
Speed is kept the same.
New kinetic energy is given by:
KE′=12m′v2
KE′=12(2m)v2
KE′=2KE
Hence, kinetic energy is doubled.