Answer :
I believe the answer is D) 15 yards per second
let's convert all of them into meter/hour
2 meters/minute = 120 meter/hour
6 miles/hour = 6x1609.34/hour = 9656.06 meter/hour
10 feet per second = 36000feet/hour = 1097.28 meter/hour
15 yards per second = 54000 yards /hour = 49377.6 metr/hour >>>> Fastest
let's convert all of them into meter/hour
2 meters/minute = 120 meter/hour
6 miles/hour = 6x1609.34/hour = 9656.06 meter/hour
10 feet per second = 36000feet/hour = 1097.28 meter/hour
15 yards per second = 54000 yards /hour = 49377.6 metr/hour >>>> Fastest