Answer:
im pretty sure its the 3rd one
If it is 90 degreees at the angle
26' wheel @ 90 rpms = 2,340 inches / min (26 x 90)
2,340 inches / min = 140,400 inches / hour (2,340 x 60)
140,400 inches / hour = 11,700 feet / hour (140,400 / 12)
11,700 feet / hour = approx. 2.216 miles / hour (11,700 / 5,280)
What are you confused by?