Concept:A Mu'adh-Dhin is the person appointed to call Muslims to prayer through the Adhan.
Explanation:Bilal ibn Rabah was a close and loyal companion of Prophet Muhammad (SAW).
He was chosen because of his strong, beautiful voice and his steadfast faith.
When the Adhan was introduced in Madinah, the Prophet appointed Bilal to give the call to prayer.
This made Bilal the first Mu'adh-Dhin in Islamic history.
Before Bilal, no one else had been assigned this noble duty.
The other names listed, such as Amr, Hamzah, and Maysarah, were not the first muezzin.
Therefore, the correct option is clearly Bilal.
Answer:B. Bilal