Correct option is A
Distance = Speed * Time
Distance = 60 km/h * 9 hours = 540 km
New time = Initial time - Time saved
New time = 9 hours - 1 hour = 8 hours
New speed = 540 km / 8 hours = 67.5 km/h
Speed increase = New speed - Initial speed= 67.5 km/h - 60 km/h = 7.5 km/h