B because all of the other ones are correct-
I got the same answer as you. Try to ask your teacher about it since it’s a math problem online or something.
Speed of the east bound cyclist is 12 mph and the speed of west bound cyclist is 15 mph.
<u>Solution:</u>
Let us assume that x is speed of slower eastbound cyclist
So, x+3 will be the speed of faster westbound cyclist
We know that distance is the product of speed and time. That is,

West-bound DATA:
Rate of speed = x+3 mph ; Time = 6 hrs ; distance = 6(x+3) = 6x+18 miles
East-bound DATA:
Rate of speed = x mph ; time = 6 hrs. ; distance = 6x miles
On solving,
Distance apart = 162



So, the rate of speed of the east bound cyclist is 12 mph and the rate of speed of the west bound cyclist will be 
Then move all terms not containing x from the center section of the inequality.
-2<x<3