Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.
(a) `C_6H_5OH`
(b) `C_6H_5NO_2`
( c) `C_6H_5 overset (oplus) CH_2`
(d) `CH_3CH=CHCHO`
( e) `CH_3CH=CH-overset (oplus) CH_2`
(f) `C_6H_5CHO`
(g) `CH_2=CHOCH_3`.