I believe it’s A, i could be wrong tho 3
In the above case we can say that power given by external agent to pull the rod must be equal to the power dissipated in the form of heat due to magnetic induction.
Part a)
when we pull the rod with constant speed then power required will be product of force and velocity
here we will have

P = 4 W
v = 4 m/s
now we will have


So external force required will be 1 N
PART B)
now in order to find magnetic field strength we can say

here we know that induced EMF in the wire is E = vBL
so power due to induced magnetic field is given by


by solving above equation we will have

1) The electric potential at a distance r from a single point charge is given by

where k is the Coulomb's constant, q is the charge and r is the distance from the charge.
The charge in this problem is

So the potential at distance

is

2) By using the same formula as before, we can find the electric potential at distance r=99 m from the charge:
I think the correct answer is a series circuit. This type of circuit is characterized by having only one path for electric current to flow. All of the components in the circuit share the same current. Hope this answers the question. Have a nice day.