Answer:
Christy did not get enough lumber.
Explanation:
Christy needs 100 inches in lumber for a bookshelf, right? Well, there are only 96 inches in an 8 foot piece of lumber, and she needs 100 inches not 96, (there 4 inches needed to get 100 inches) 96 (obviously) is less than 100, so in this case she needs two pieces of lumber, there will be extra but it will be good to have extra just in case.