The correct option is C Distance moved by the particle in time t=πB0α is πv0B0α
Since →v⊥→B , path of the particle must be circular.
In uniform magnetic field , speed of the particle remains constant.
∴ Distance travelled by particle in time t=πB0α is d=v0×t
=v0×(πB0α)
Hence, options (b) and (c) are the correct answers.