Two particles Y and Z emitted by a radioactive source at P made tracks in a chamber as illustrated in the Fig. 1.134. A magnetic field acts downward into the paper. Careful measurements showed that both tracks were circular, the radius of Y track being half that of the Z track. Which one of the following statements is certainly true?
A. Both particles Y and Z carried a positive charge
B. The mass of particle Z was one half that of particle Y
C. The mass of particle Z was twice that of particle Y
D. The charge of particle Z was twice that of particle Y