Take a look at the passage again:
While eating the plate of sesame chicken, Maria
was thankful for her skill with chopsticks. Eating utensils that
required only one hand to use. For Maria's left hand was pinned to the booth
by Hunter, her five-year-old son who lay sleeping after a long day of shopping
at the mall.
You chose the first part, While eating the plate of sesame chicken, Maria was thankful for her skill with chopsticks. This part has a main clause: Maria is the subject; was is the verb. A fragment will not have a main clause.
Go back to the passage to try again.