A sequence of pictures of polypeptide synthesis shows a ribosome holding two transfer RNAs. One tRNA has a polypeptide chain attached to it; the other tRNA has a single amino acid attached to it. What does the next picture show?
(a) The polypeptide chain moves over and bonds to the single amino acid
(b) The tRNA with the amino acid leaves the ribosome
(c) The amino acid moves over and bonds to the polypeptide chain
(d) The tRNA with the polypeptide chain leaves the ribosome