Which of the following does the electorate consist of? a. citizens eligible to vote. b. the people who vote in an election. c. people who...

It would be a
good idea for you to look in your textbook or in your lecture notes for this answer.  The reason
for this is that electorate is a term that can be used in many ways, depending on the
context.

Of the choices that you have given here, both A and B show
definitions of electorate that can often be seen in American political writing.  For example,
href="https://www.voterparticipation.org/our-mission/the-rising-american-electorate/">in
this link, we can see a discussion of the rising American electorate.  This source
goes on to tell us that much of the rising American electorate is not registered to vote.  That
means that B is clearly not the sense in which they are using the term.  Instead, they are using
the term to refer to all those who would be able to vote if they registered.  On the other hand,
we can see in this link a use of the term electorate to mean those people who actually voted
in the election.

Thus, the term can be used in both ways.  It is likely that
your book or teacher uses it in one of these two ways and you will need to determine which of
those it is.