It costs $5 to buy 2 pounds of fish tank gravel. What is the unit rate in dollars per pound? Answer Questions were confusing so i changed it to a decimal!

It costs $5 to buy 2 pounds of fish tank gravel. What is the unit rate in dollars per pound? A.$2.50 per pound B.$0.40 per pound C.$3.00 per pound D.$2.00 per pound