The correct option is (A) i.e. 180° to the magnetic field.
Explanation:
The magnetic force on a charged particle is given as: F = qvBsinФ
B is the magnetic field.
q is the charge on the particle.
v is the velocity of the charged particle.
Ф is the angle between magnetic field (B) & the velocity of charge (v).
⇒ F = qvb sin Ф
When Ф = 180,
& sin Ф = 0
⇒ F = 0
therefore, there is no magnetic force when the magnetic field is parallel or anti-parallel to the velocity of the particle.
