Final answer:
By dividing the total cost of $43.25 by the number of gallons which is 12.5, we find that the cost of one gallon of gas is $3.46.
Step-by-step explanation:
To find out the cost per gallon of gas, we need to divide the total cost by the number of gallons. Jayden's dad paid $43.25 for 12.5 gallons. So, we divide $43.25 by 12.5 gallons to find the cost per gallon.
$43.25 ÷ 12.5 gallons = $3.46 per gallon
Therefore, the correct answer is A. $3.46 per gallon.