According me to do well in D&D questions in real exam there are two options.
Option 1. Solve all questions in one attempt including D&D questions. Option 2. Solve others questions but dont solve D&D questions in first attempt.
If you will solve all questions in one attempt there is possiblity that you will not be able to solve some questions so you need to revist.If you revisit all your previous answers for D&D questions will be delete. if you are dead sure that you will be able to solve all questions in single attempt then fine but i think it is not possible for everyone.
I will prefer to go for option 2 which i did in exam.First i solved all question but i did not solved D&D questions at all.Then i revisted and solved all D&D questions and also solved those non D&D questions which i maked in first attempt.
I personally fee that option 2 is more suitable then option 1.