Driving question

This is a tricky one, so think about it very carefully!

Here is a driving test question.
If you get it wrong you may be too old to drive.

Traffic Question?

Q:

You are driving along a narrow two lane road with aNO PASSING 
FOR 2 MILES sign posted, and you come upon a bicycle rider.
Do you:

(a) Follow this slow-moving bicycle rider for the next 2 miles, or(b) Do you break the law and pass?

Which is the correct choice? 

Thanks Graham