To answer this question, you need to have knowledge about the historical forts in Delhi.
Option A) Mughal Fort - This option is incorrect because the fort built by Sher Shah Suri is not known as the Mughal Fort.
Option B) Mud Fort - This option is incorrect because the fort built by Sher Shah Suri is not made of mud.
Option C) Old Fort - This option is correct because the fort located on the Delhi-Mathura road to Agra and built by Sher Shah Suri is known as the Old Fort. It is also known as Purana Qila.
Option D) Red Fort - This option is incorrect because the Red Fort in Delhi was built by the Mughal emperor Shah Jahan, not Sher Shah Suri.
The correct answer is Option C) Old Fort. This option is correct because the fort built by Sher Shah Suri on the Delhi-Mathura road to Agra is known as the Old Fort or Purana Qila.