The Permanent Settlement of 1793, introduced by the British, made zamindars the owners of land and the collectors of revenue. The zamindars now had significant control over the land, which they could manage, sell, or lease. While the system benefited the British by securing a stable revenue, it often led to exploitation of the peasants. Zamindars gained considerable power through this arrangement.
Thus, the correct answer is (D) They gained significant control over land.