Concept:The Prophet's Mosque in Madinah was built with the combined effort of the Prophet and his companions.
Explanation:After migrating to Madinah, the Prophet Muhammad (SAW) selected the site for the mosque.
The Prophet and his companions began the construction work together.
They carried stones and built the foundation with dedication.
The first person to begin the foundation of the mosque was 'Ammar ibn Yasir.
He worked energetically under the Prophet's supervision.
The other listed men, Abdullah ibn Ubayy, Abu Ayyub al-Ansari, and Anas ibn Malik, are not recorded with this particular honour.
Hence, the correct choice is option A.
Answer:A. 'Ammar ibn Yasir