C is what i always have so ima go with C.
Explanation:
Let 
is the mass of proton. It is moving in a circular path perpendicular to a magnetic field of magnitude B.
The magnetic force is balanced by the centripetal force acting on the proton as :
r is the radius of path,
Time period is given by :
Frequency of proton is given by :
The wavelength of radiation is given by :
So, the wavelength of radiation produced by a proton is 
. Hence, this is the required solution.
The Law of the Conservation of Energy is stating that the total mechanical energy is always conserved or in simpler terms, not used or saved.
The time component is needed. The acceleration is the change of velocity divided by the time in when this change of velocity happens.
