The correct answer is option 'C', which states that the large mansion of merchants was not constructed by the king. Let's explore the various construction activities carried out by the king to understand why this option is correct.

Bazaars:
The construction of bazaars was one of the activities undertaken by the king. Bazaars are marketplaces where goods are bought and sold. These marketplaces are essential for trade and commerce, and the king would have recognized their importance in promoting economic growth and generating revenue. The construction of bazaars would have provided a space for merchants and traders to conduct business, contributing to the overall development of the kingdom.

Wells:
The construction of wells was another significant activity carried out by the king. Wells are essential for providing a reliable source of water for the community. They ensure a consistent water supply for drinking, irrigation, and other daily needs. By constructing wells, the king would have been prioritizing the well-being and sustenance of his people. This initiative would have enhanced the quality of life and contributed to the agricultural productivity of the region.

Mosque:
The construction of a mosque is a religious activity and often undertaken by rulers to demonstrate their piety and devotion. Mosques are places of worship for Muslims and serve as community centers for religious, educational, and social activities. The construction of a mosque would have indicated the king's commitment to fostering religious harmony and providing a space for spiritual growth and communal gatherings.

Large mansion of merchants:
This option states that the construction of a large mansion of merchants was not carried out by the king. While it is not explicitly mentioned why the king did not undertake this specific construction activity, it can be inferred that the construction of a merchant's mansion may not have been a priority for the king. Instead, the king would have focused on projects that directly benefited the community as a whole, such as bazaars, wells, and religious structures like mosques.

In conclusion, the correct option 'C' indicates that the construction of a large mansion of merchants was not carried out by the king, possibly because it was not considered a priority compared to other construction activities that directly benefited the community.