R,S-configuration is a useful tool for determination of enantiomers, diasteromers and homomers. If configuration of all chiral centers are opposite then structures are enantiomers, if all chiral centers have same configuration then they are homomers and if some have same confguration and some have opposite configuration then they are diastereomers.
Which of hte following is not diastereomer?
A. I and III
B. II and III
C. III and IV
D. II and IV