Leakage radiation from the x-ray tube cannot exceed which of the following at a distance of one meter?

a. 6.45 x 10-6 coulomb/kg/hr (25 mr/hr)
b. 1.29 x 10-5 coulomb/kg/hr (50 mr/hr)
c. 1.94 x 10-5 coulomb/kg/hr (75 mr/hr)
d. 2.58 x 10-5 coulomb/kg/hr (100 mr/hr)