Given that velocity of a particle is making an acute angle with the magnetic field. Velocity of a particle is resolves into two components. Magnetic field always change the direction of the velocity. One component is perpendicular to the magnetic field that is Vsinθ and another component is parallel to the magnetic field that is Vcosθ. Vertical component of a velocity is perpendicular to the magnetic field. Then force will act on the charged particle. Because of the vertical force(Vsinθ), the particle will make a circular path. Because of the two components of the velocity the particle will move in a helical path. This path will maintain the uniformity. So option C is correct.