A certain number of people are sitting in a straight line facing north. Only three people are sitting between D and I. There are only two people sitting between K and O. I is sitting to the immediate left of O. No one is sitting to the left of D. Only one person is sitting to the right of O. How many people are sitting in the row?

Given: ​A certain number of people are sitting in a straight line facing north.

Only three people are sitting between D and I.

There are only two people sitting between K and O.

I is sitting to the immediate left of O.

No one is sitting to the left of D.

Only one person is sitting to the right of O.
Based on the given conditions seating arrangement will be : 

D, K, _, _ ,I,O, _ 
or

Thus, the total number of people in the row is 7.
The correct answer is (d).​​