Read the following information carefully and answer the question given below.

Eight friends—Rahul, Mahesh, Priya, Dinesh, Prasad, Praveen, Ramu and Aruna sit in a row having chairs numbered one to eight in ascending order from left to right. They all are facing north direction.
Priya sits on the chair numbered six. There are exactly two persons between Priya and Rahul. Mahesh and Aruna always sit adjacent to each other. Ramu sits adjacent to neither Rahul nor Priya. Prasad never sits on a chair having an odd number on it. Neither Mahesh nor Aruna sits on chair numbered four. There is only one person between Praveen and Mahesh. Prasad sits on the right (not an immediate right) of Dinesh, and Dinesh never sits adjacent to Praveen.

Which of the following pairs sits at the two extreme ends?