The largest standing army of the Sultanate directly paid by the State was created by

Correct answer: Alauddin Khilji

Explanation: The correct answer is B. Alauddin Khilji. Alauddin Khilji was the first Sultan of Delhi to organize a large standing army that was directly paid and maintained by the state. He introduced several military reforms such as dagh (branding of horses) and chehra (descriptive rolls of soldiers). His purpose was to curb the power of nobles and prevent rebellions, and to defend the Sultanate from Mongol invasions effectively.