The practice of military governorship was first introduced in India by the Greeks.

The Greeks, specifically the Macedonian ruler Alexander the Great, invaded the northwestern parts of the Indian subcontinent in the 4th century BCE. After Alexander`s conquests, his generals and successors, known as the Diadochi, established their rule in various regions, including parts of present-day Pakistan and northern India.

The Greek successors, known as the Seleucids, adopted the practice of appointing military governors or strategoi to govern and administer these conquered territories. These military governors had both military and administrative authority and were responsible for maintaining control and collecting taxes.

The concept of military governorship was further developed and continued by subsequent foreign invaders and rulers in India, such as the Shakas, Parthians, and later the Mughals. However, the practice was initially introduced by the Greeks under the leadership of Alexander the Great and his successors.

Therefore, the correct answer is the Greeks.