A dipole electric field is generated outside the surface of a sphere, if the charge per unit area on the surface of that sphere is distributed proportionally to cos( 0). If the sphere has a radius r, and there is a total charge of Qo on the upper hemisphere and -Q, on the lower hemisphere, what is the expression for the charge density pc(r, 0,4) in spherical coordinates?

Ohm's law tells you that i = v/r where v is equivalent voltage and r is equivalent resistance of the circuit
since all circuits have the same voltage, your question is really asking which circuit has the lowest total resistance, since the lower the resistance, the higher the current
circuit a has a resistance of 5 ohms; circuit c is in series so has a resistance of 10 ohms; circuit b is in parallel and therefore has a resistance of 2.5 ohms (review your notes on adding resistances in parallel and series); therefore b has the highest current

The correct answer should be b let me know if i’m wrong

Answer (d) the universe had cooled enough for atoms to combine, protons and neutrons were too far apart to form nuclei;