Explain how drinking through a straw illustrates fluid flowing from high-pressure to low-pressure areas.

the pressure in the straw is reduced, but the atmospeheric pressure on the surface of the liquid stays the same.

Drink a pepsi cherry iced fruit shoot apple juice milkshake mocktail

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