B 0.4 m should be correct if not it is A
I feel like it expresses time, but if there is another answer and they say otherwise, then they are probably right.
Hope this helps!
The moon is talking to thecat at night that’s why
The magnitude of the force on the charge by the influence of the magnetic field will be 6.6*10^-3 N
<h3>What is magnetic force?</h3>
Magnetic force, attraction or repulsion that arises between electrically charged particles because of their motion.The magnitude of the magnetic force acting on the charge is given by:

where
The magnitude of the charge 
The velocity of the charge 
The magnitude of the magnetic field 
The angle between the directions of v and B 
By substituting the values we will get:


Hence the magnitude of the force on the charge by the influence of the magnetic field will be 6.6*10^-3 N
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