There are currently 3 types of certifications. There is a Marketo core platform certification, an analytics certification, and a certified consultant certification. When you are asking about the partner exam, i believe you are talking about the certified consultant exam.
The core platform certification is for day to day users of Marketo. Here is what is covered for this exam: http://docs.cdn.marketo.com/MCE-Roadmap-Complete-Updated.pdf
The analycis certification is for customers who use RCA. Here are the details for this exam: http://docs.cdn.marketo.com/RCA-Roadmap-2013.pdf
Both of these two certifications can be taken online and are multiple choice
The certified consultant exam is usually for partners. MCC’s must pass ALL Specialization Exams to gain Certified Consultant status. In addition, you must attend the Marketo Partner Strategy Workshop and complete the Strategy Case Study Homework. That is how you get that third status.