The Oxygen Consumption (In Milliliter/pound/minute) for a Person Walking at X

The oxygen consumption (in milliliter/pound/minute) for a person walking at x mph is approximated by the function ​ ​
Where the oxygen consumption for a runner at x mph is approximated by the function
​ ​
At what speed is the oxygen consumption the same for a walker as it is for a runner? What is the level of oxygen consumption at that speed?
​

A) 3.1 mph, 100.6 mL/lb/min
B) 7.6 mph, 95.6 mL/lb/min
C) 4.6 mph, 65.6 mL/lb/min
D) 5.6 mph, 75.6 mL/lb/min
E) 7.1 mph, 90.6 mL/lb/min