D) Muhammad-bin-Tughlaq is the correct answer.

Explanation:
Muhammad-bin-Tughlaq was a sultan of the Tughlaq dynasty in the Delhi Sultanate, who ruled from 1325 to 1351. He is known for his ambitious and innovative ideas, many of which were not successful. One of his attempts was to organize the army on the decimal system after the Mongol pattern.

1. Decimal System:
The decimal system refers to a system of numbering based on the number 10. In this system, numbers are represented using the digits 0-9. The decimal system was widely used by the Mongols, who were known for their military prowess and organization.

2. Mongol Pattern:
The Mongols had a highly organized military system based on a decimal structure. They divided their army into units of 10, with each unit led by a commander. These units could be further combined to form larger units, such as units of 100 or 1000. This hierarchical structure allowed for effective command and control of the army.

3. Muhammad-bin-Tughlaq's Attempt:
Muhammad-bin-Tughlaq was impressed by the military organization of the Mongols and wanted to implement a similar system in his own army. He believed that organizing the army on the decimal system would improve its efficiency and effectiveness in battle.

4. Implementation and Challenges:
Muhammad-bin-Tughlaq began the process of organizing the army on the decimal system by dividing it into units of 10, with each unit led by a commander. However, the implementation of this system faced several challenges.

- Resistance from the nobles: The nobles and military commanders were resistant to the new system as it threatened their power and authority. They were accustomed to the traditional feudal system where they held significant control over their troops.

- Lack of training and discipline: The new system required extensive training and discipline to ensure that the soldiers understood their roles and responsibilities within the decimal structure. However, the army lacked the necessary training and discipline to effectively implement the system.

- Administrative challenges: Managing and coordinating a large army organized on the decimal system was a complex task. The logistics and administrative challenges proved to be overwhelming for the sultanate, which was already facing economic and political instability.

5. Abandonment of the System:
Due to the challenges and resistance faced, Muhammad-bin-Tughlaq had to abandon his attempt to organize the army on the decimal system. The system proved to be impractical and ineffective in the context of the Delhi Sultanate.

In conclusion, Muhammad-bin-Tughlaq, the sultan of the Tughlaq dynasty, tried to organize the army on the decimal system after the Mongol pattern. However, due to various challenges and resistance, the system was ultimately abandoned.