Answer: D
Step-by-step explanation:
Genocide is the mass execution of a certain ethnic group for no proper reason whatsoever while ethnic cleansing is the process of segregating people based on their ethnicity.
Let's take an example:
Say there were 2,500,000 marbles in a country and 700,000 were orange, and the rest were pink. (Just an example).
Genocide would be the pink marbles making the orange marbles move out of the country by using violence.
While ethnic cleansing would be the pink marbles separating the orange marbles from the rest of the society and giving them limited privileges compared to the pink marbles.
Both are very bad although genocide is worse.
The well known example of genocide is the holocaust. Genocide is also ethnic cleansing, but ethnic cleansing isn't always genocide also.
Hope that helped a lot.
:)