Good questions.
Terrible answer: Choose the correct answer for the test. And follow the manufacturer's recommendations when operating the aircraft.
The tough part with these performance problems is that everything is always a trade off. In real life, we're constantly trading something for something else.
At this point, I'd say, without really knowing your background, that it's more important for you to be able to discern the apparent contradiction and be able to weigh the difference between the two choices--as you've done.
Good job.
Later when you're in the real airplane and faced with slippery runways and deactivated equipment and well documented performance numbers you'll do well to carefully consider all of the various factors affecting your flight.
Sorry to evade your direct question, but every aircraft, every airport and every set of conditions is different. There are lots of variables (weight, thrust, temp/press., rwy length, obstacles, installed (deactivated) equipment) that affect V1. You'll be provided with tons of information and be expected to make a quick and reasonable decision (JUDGMENT) while considering *all* of it and dismissing *none* of it.
Good luck!
