I would assume you are correct on this one.
You would want a plan to help you achieve your goals. All the other things are good, but they aren't most important. You would want to know what you need to do or achieve at each step in time to reach your goal. This makes your big goal into tinier goals, so each one is easier to reach- and you can see the significance of your work at a faster pace.
"B" is the correct answer.
I hope this helps!
~kaikers