I'm not entirely sure that I understand you problem. I am assuming that your a)
is meant to be the subsection numbering, and that "Blah blah blah" is mean to be the title, and that you have not exhibited the text of the subsection at all.
Subsection are numbered (lettered?) automatically, the argument is the title:
\subsection{Blah blah blah}
Then the text of the subsection...
will generate something like:
3.1 Blah blah blah
Then the text of the subsection...
where the c)
To change the formatting of the subsection header, you either hack the class definition or choose a more flexible class (like memoir).