A beam of protons with a velocity of `4 xx 10^5 m s^(-1)` moves in the direction of uniform magnetic field. It makes an angle of 37° with the magnetic field and follows a helical path. If the time period of helix is `2 xx 10^(-7) s`, then its pitch will be
Options:
(a) 2 cm
(b) 4 cm
(c) 8 cm
(d) 6cm