@Tor-EinarJumbo gives what I think is the correct answer, but I would like to add another that addresses @SebastianRedl's comments.

Here is [the complete data from the poll][1]. The question about Agrabah had only three responses: 'support bombing', 'oppose bombing' or 'not sure'. Presumably a response of 'I've never heard of that country.' was filed under 'not sure' (though it's also reasonable to believe that people might oppose bombing of countries they had never heard of, or even countries they knew to be fictional).

The 41% figure given for Trump supporters is of all responses. So the full response list is:

 - 41% support
 - 9% oppose
 - 51% not sure (sic. Rounding errors)

The figures of around 50% 'not sure' is fairly constant across all the Republican primary supports, with the happy exception of George Pataki, whose supporters returned a 100% 'not sure'. Presumably George Pataki scores high among people who listen to questions and know the names of countries.

The 50% 'not sure' is also fairly constant across all other demographics.

  [1]: http://www.publicpolicypolling.com/pdf/2015/PPP_Release_National_121715.pdf