A proportional relationship has a unit rate of 3 to 1. Which situation below represents this relationship?

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1 point
A car travels 326 miles in 4 hours
Purchased 27 CD's for $9.00
A pump moves 42 gallons in seven minutes
32-ounce bag of gummy bears for $4.00

The situation that represents a proportional relationship with a unit rate of 3 to 1 is: A pump moves 42 gallons in seven minutes.