Answer: All 6 will go to the Democratic candidate
Step-by-step explanation:
Even though there is no Constitutional basis, states usually give all their electoral votes to the candidate with the majority vote in their state. Mississippi is one of those states.
So long as a candidate receives the majority of the votes, they will get all 6 of Mississippi electoral votes. For instance, Senator McCain won 724,597 votes to Obama's 554,662 in 2008 and thus got all 6 electoral votes.
The Democratic candidate here will therefore receive all 6 electoral votes.