Which of the folowing statements relative to IUPAC nomenclature for alkenes and cycloalkenes is INCORRECT?
a.the position of a double bond in a parent chain is given by a single number.
b.alkyl groups take precedence over carbon-carbon double bonds in determining the direction in which the parent chain is numbered.
c.a number is not needed to specify double bond position in ethene and propene
d.a number is not needed to specify double bond position in unsubstituted cycloalkenes with one carbon-carbon double bond