The world's longest river, the Nile, flows through the continent of Africa. It is approximately 6,650 kilometers (4,130 miles) long and is a significant geographical feature in northeastern Africa. Therefore, the correct answer is (B) Africa.

The sea that does not belong to Russia is (B) Baltic Sea. The Baltic Sea is located in Northern Europe and is bordered by several countries, including Sweden, Finland, Denmark, Germany, Poland, Latvia, Estonia, Lithuania, and Russia. It is not entirely enclosed by Russia. The other seas mentioned (Laptev Sea, Kara Sea, and White Sea) are all located in the Arctic and subarctic regions and are part of the Russian territory.

Muhammad- bin - Tughluq was a brilliant scholar. He was a knowledgeable person and well versed in astronomy, poetry, philosophy, logic, medicine, physical science, and mathematics.