Which units are used to express kinetic energy

Oh !  You just said "energy". So it's going to be measured in Joules.

b.transmitters send radio waves, and receivers capture radio waves.

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.