Based on your description of the artwork featuring a "fat man with a big red cloth," it seems that color, particularly the use of the bold red cloth, is likely the element of art that creates emphasis. The bright red would draw attention and create a focal point in the piece.
As for balance, the size and placement of elements (the man and the cloth) may also contribute to the overall composition, possibly using shape or form. However, without seeing the artwork, it's challenging to determine which elements are used most effectively.
If emphasis is primarily created through the bold use of red, then "color" would be the correct answer to your question.