Best date for exam

Analyn,
From these four days that you had proposed, I believe that you could sit for your exam on Thursday the 28th of December 2017, and expect to do well. On that day transiting Mars will aspect favourably your natal Sun. Transiting Moon will trine your natal Jupiter (which represents your luck.) As transiting Mars will conjunct your natal Saturn (the planet which helps us do everything right,) it will give a boost to your mental power. Good luck to you.