Nation X is a democratic country with three major political parties.

In the second clause, "those leaders" can be interpreted in two plausible ways.
1) those leaders = The first ten leaders
2) those leaders = Those (among first ten leaders) who were members of Party A

Thanks to the option choices, we can disambiguate the statement. Still, the clarity of the question can be improved unless its vagueness is intentional.

KarishmaB - can you help explain how the answer to the second dropdown is "none" ?

­My name is not KarishmaB but I can try explaining. Basically, the question is asking us: among the years that A was in charge of politics in Country X (i.e. when a member of party A was leader,) are there any leaders that had at least 50% of approval ratings from the other two parties. Essentially, we must look at all of the years in which a member of party A was in charge, we can see that there are 5 years where this is the case, however amongst those 5 years there is no instance in which members of party B and C had an approval rating greater than 50% for that leader. 

What is happening this question . Can someone Pls explain . It says its Approval rating , but the graphs of any single person exceeds 100%.­

 
­The key thing to understand here is that the information given for the passage has to be understood very precisely. 
So, researchers asked some people who identify themselves as members of Party A, Party B or Party C. These people were asked to give their approval ratings for the 10 leaders of Nation X. 
When asked about Leader 1, the people who identify themselves as members of Party A approved Leader 1 wholeheartedly. Those who identify themselves as members of Party B or Party C approved Leader 1 with a lower rating. 

When asked about Leader 2, the people who identify themselves as members of Party B approved Leader 2 wholeheartedly. Those who identify themselves as members of Party A or Party C approved Leader 2 with a lower rating. 

This interpretation is key to understanding how the graph is constructed. The highest approval rating for a particular leader is indicating that the leader belongs to that particular party (Leader 1 belongs to Party A while Leader 2 belongs to Party B)


Now, coming to the questions, 
To answer this question, check the highest approval rating for each of the 10 leaders. The leaders having the highest approval rating from people who identify themselves members of Party A must belong to Party A. There are 5 such instances (Leaders 1, 4, 6, 8, 10).
Here, those leaders refer to Leaders that we identified as belonging to Party A i.e. Leaders 1, 4, 6, 8, 10. 
For these leaders, we must have approval rating of more than 50% from members of each of the three parties. Thus, for these leaders, all the three bars must be more than 50% tall. There is no such leader.­

Vinit800HBS , Check the 7th leader ; in his case all the three bars are more than 50%. MartyMurray , 
I think 'none' should be the answer because we dont  know  the  total base value of  the number of members of each political party.
­

Thanks chetan2u...
The keyword here is "those leaders " . We need to check only for the leaders such as 1 , 4 , 6 , 8 and 10. And none of those leaders have approval ratings of more than 50% of members of each political parties.

Yes, you are correct. That is why we don’t consider 7th leader. (Your question above)

Posted from my mobile device

Though Leader 7 has more than 50% approval rating from members who identify themselves as members of Party A, Party B, or Party C, Leader 7 actually belongs to Party B. So, leader 7 is not part of "those leaders who belongs to Party A".

Hence, looking at Leader 7 doesn't matter.

Hope that clears the doubt

Posted from my mobile device

Is it me or does the english suck?

einstein801 it's you XD jk