Polarization of acrolein as
(a) \stackrel{+\delta}{ C } H _2= CH -\stackrel{-\delta}{ C } HO
(b) \stackrel{-\delta}{ C } H _2= CH -\stackrel{+\delta}{ C } HO
(c) \stackrel{-\delta}{ C}H _2= CH -\stackrel{+\delta}{ C } HOc
(d) \stackrel{+\delta}{ C } H _2= CH -\stackrel{-\delta}{ C } HO
(d) \stackrel{+\delta}{ C } H _2= CH -\stackrel{-\delta}{ C } HO