7. (8 marks) Draw line/angle structures corresponding to the following IUPAC names: 7a) N,N-diphenylpropanamide 7b) (R)-1,3-butanediamine 7c) 2,6-dibromo-4-chloro-3-ethyl-5-isopropylphenol 7d) (5R, 3Z)-5-fluorohex-3-en-1-oic acid