The correct answer is option C) Saadat Khan.

Explanation:
Avadh, also known as Oudh, was a region in present-day Uttar Pradesh, India. It was historically ruled by various dynasties and governors. Saadat Khan, also known as Burhan-ul-Mulk, was an influential nobleman in the Mughal Empire. He served as the governor of Avadh from 1722 to 1739.

During his tenure as the governor, Saadat Khan established a semi-independent state in Avadh. He effectively ruled over the region and laid the foundation of the Avadh Nawabi dynasty. Saadat Khan's appointment as the governor of Avadh marked the beginning of a hereditary rule in the region.

Saadat Khan's descendants continued to rule over Avadh as Nawabs (governors) for several generations. The dynasty reached its peak under Nawab Asaf-ud-Daula, who was a prominent ruler known for his administrative reforms, cultural patronage, and architectural achievements. Under the Nawabs of Avadh, the region experienced significant economic and cultural growth.

It is important to note that the other options mentioned in the question are not correct. Safdar Jang was the Nawab of Avadh who succeeded Saadat Khan as the governor, but he did not establish Avadh as a hereditary possession. Salabat Jang, on the other hand, was a ruler in the Deccan region and had no direct connection to Avadh. Therefore, the correct answer is Saadat Khan, who laid the foundation of the hereditary rule in Avadh.