The sample mean is x ≈ 92.9. let x be a random variable representing glucose readings taken from gentle ben. we may assume that x has a normal distribution, and we know from past experience that σ = 12.5. the mean glucose level for horses should be μ = 85 mg/100 ml.† do these data indicate that gentle ben has an overall average glucose level higher than 85? use α = 0.05.

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