Answer:
a. Quran
Step-by-step explanation:
Quran is the sacred book of Muslims which was revealed to Prophet Muhammad (Peace Be Upon Him) by Allah (God).
The Day of Judgement (Qiyamah) is the day when every person will be held accountable for their deeds in the worldly life.
Dawah is the preaching of Islam and invitation by Muslims towards their brethren to embrace the religion of Islam.
Jannah is the paradise or heaven.
Coming back to the question, the Holy Book which was revealed to Prophet Muhammad (PBUH) is asked.
The correct answer is a because Quran is the sacred Book that was revealed to Prophet Muhammad (PBUH).