Answer: Despite: "The last contestant really did his best to get the grand prize despite the last question being so difficult." This emphasizes the difficulty of the question and the contestant's effort in overcoming it.Although: "The last contestant really did his best to get the grand prize although the last question was so difficult." This is similar to "despite," but perhaps slightly less emphatic.Even though: "The last contestant really did his best to get the grand prize even though the last question was so difficult." This is very similar to "although."But: "The last contestant really did his best to get the grand prize, but the last question was so difficult." This version suggests a contrast – the effort was made, but the difficulty of the question might have hindered success.However: "The last contestant really did his best to get the grand prize; however, the last question was so difficult." This is similar to "but," offering a more formal tone.The best choice depends on the specific context and the intended emphasis. All options correctly connect the two clauses and create a grammatically sound sentence. Note that I have also corrected the spelling of "grand prize."Step-by-step explanation: