The right answer is D) floating freely in the cytoplasm.
A prokaryote (or Prokaryota) is a living being whose cell structure has no nucleus, and almost no membranous organelles (the only exception being thylakoids in cyanobacteria).
In prokaryotes there is no nucleus or endoplasmic reticulum so systematically the answers A, B and C are false, so only the D remains as a valid answer.
