Concept:Al-Amin means "the trustworthy one."
It was the title given to Prophet Muhammad due to his honesty and reliability.
Explanation:Prophet Muhammad was widely known for his truthfulness even before he became a messenger.
The people of Makkah gave him the title Al-Amin because he never told a lie.
They considered him the most upright and honest person among them.
People used to keep their valuables with him for safekeeping, trusting him completely.
Thus, Al-Amin means "trustworthy person."
It does not refer to being a posthumous child, memorizing the Qur'an, or being a messenger.
Those were not the reasons for this title.
His consistent honesty earned him this noble reputation in society.
Answer:D. trustworthy person