A He needed hundred of quilt squares for this project.
B She filled her living room with dozens of tulips.
C Seven thousands of people showed up for the concert.
D Does anyone know why Steve ordered five dozens of eggs?
B is correct, dozens is used when you don't specify how many dozens there are. if it is specified then it would just be three dozen or five dozen or something like that. Same with thousands and A. needs to be reworded to even make actual sense
