Sally's use of the photos is "an infringement of Isaiah's copyright only if consumers are confused".
Option: C
Explanation:
If consumers are reading or going through Sally's book which is about photography, in such cases someone's copyrighted material is never welcomed, still Sally xeroxed the pictures from Isaiah's book. This shows her book is not plagiarism free, but it can be accounted when readers raise some doubts and go for further cross checking.
A legal methods to safeguard the creation of an artist, a form of intellectual property that grants the author exclusive rights to print, distribute and use is basically a copyright. This means that no-one else can use or publish any created content by the developer without the author's permission.