Sometimes it is easier to specify a regular language using a
regular grammar rather than a regular expression or regular
definition. A regular grammar is a context free grammar where every
production's right hand side has at most one nonterminal, which must
be the last symbol.
Do problem 3.7, part f only, but give your answer as a regular
grammar rather than a regular definition. If you want to learn more,
you can do the regular definition too.