Most apps that designed specifically for drawing has the ability to save the work in Vector Format. This format makes you able to re-size the drawing (Either smaller or Larger) Without losing any quality. Other format tend to make the image become blurry when edited into larger size.
Not only that, Drawing apps will provide you with the ability to draw basic shapes in a perfect proportion, which is very useful during the sketching phase.
The correct answer to this question is letter "a. total stopping distance." In an emergency situation, your total stopping distance is the distance you will travel between seeing the danger and putting your foot on the brake pedal. Hope this helps answer your question.