This is more of a database question than a perl question, but I can see how people could find the answers helpful.

I'd start by learning about Database Normalization: http://dev.mysql.com/tech-resources/articles/intro-to-normalization.html

In this specific case option 2 sounds like it might be the closest to a normal form.

Of course option 1 will work, it just probably ain't the greatest.

I wouldn't do Option 3. While Perl will have no trouble parsing this field, other applications might. It also limits the usefulness of the database.