How did fossil records support the existence of a supercontinent?
Similar fossils were found in different continents.
Fossil records showed how old the continents were.
Similar fossils provided evidence that a meteor hit Earth.
Fossil records provided evidence that dinosaurs existed.

The answer is b.the gaseous state is electrically positive, while the plasma state is electrically negative. 

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