Jose has a board that is f feet long. He cut the board into pieces that were each 3/4 foot long. He used all of the pieces and built 6 shelves for a bookshelf. Which equation can be used to find the length, in feet, of each piece?

A. f + 3/4=6
B. f ÷ 3/4=6
C. f-3/4=6
D. 3/4f=6