Explanation
The necessary part of the word "Diploma" is the curriculum, which refers to the specific set of courses or program of study required to earn the diploma. A diploma is a certificate or document that indicates that a person has successfully completed a particular course of study or program of education. The curriculum outlines the knowledge and skills that a student must acquire in order to meet the requirements for the diploma. The other options listed, Principal, Employment, and Graduation, are not necessary parts of the word "Diploma."
