Answer
Blue
Work Step by Step
If you fold all the faces over, you will notice that the blue is the one that faces directly opposite and on top of the red face. Therefore, the answer is the blue face.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.