Review the passage:
Chewing the dry, tough, whole-grain bread bought from the health food store.
Lorena tried to enjoy her lunch. Fantasizing about
a juicy cheeseburger on a soft white bun did not improve the taste of the
soy product sandwiched between leaves of organic lettuce.
You chose the second part, Lorena tried to enjoy her lunch. This part has a main clause: Lorena is the subject; tried is the verb. A fragment will not have a main clause.