Option d is the correct answer. Marco Polo has mentioned about Pearl Fishery of Tuticorin in South India in his travel account. He visited India in the late thirteenth century and described the pearl fishing industry and trade in Tuticorin, which was then under the Pandya kingdom. Option a is correct: Sharaf Qai was a minister of Allauddin Khilji. He was the revenue minister who helped implement the economic reforms of the Sultan. Option b is correct: Under Giyasuddin Tughluq Muqtis were warned not to ill-treat any of their officials for small amounts taken over and above their salaries. Muqtis were the holders of iqta, a system of tax farming introduced by Iltutmish. Giyasuddin Tughluq tried to reform the iqta system and curb the corruption and oppression of the Muqtis. Option c is correct: The Arabic work masalik-i-Absar gives description of the functioning of Iqta system under Muhammad bin Tughluq. Masalik-i-Absar was written by AlUmari, a Syrian scholar who visited India in the fourteenth century. He gave a detailed account of the institution of iqta and its administration under Muhammad bin Tughluq