This refers to the academic plan which you select to complete your graduate degree.
Plan A (Thesis) includes a minimum of 30 semester credits of graduate course work and a master's thesis for which you may receive no more than four graduate credits in your area of specialization. You will also complete an oral or written comprehensive exam.
Plan B (Research Paper) includes a minimum of 30 semester credits of graduate course work and a research paper or culminating project approved by your graduate committee. You will also complete an oral or written comprehensive exam.
Plan C (Additional credits) includes a minimum of 34 semester credits of graduate course work with an oral exam conducted by your committee or a written comprehensive examination administered by your academic department.
More information on Plan B papers, thesis submission and scheduling exams is available in Graduate Procedures.