A positively charged particle (alpha-particle) projected towards the west is deflected towards the north by a magnetic field. Find the direction of the magnetic field and name the rule used to find it.
a) Magnetic field direction: Upwards; Rule: Fleming's Right-Hand Rule
b) Magnetic field direction: Downwards; Rule: Fleming's Left-Hand Rule
c) Magnetic field direction: North; Rule: Right-Hand Thumb Rule
d) Magnetic field direction: South; Rule: Left-Hand Thumb Rule