Why is the main qualification to sit for the exam limited to bachelor’s degrees for Category A?

Good question. We’re not really sure, but in general the degrees authorized by the USPTO to allow one to sit for the patent bar exam cover the majority of the fields one would be required to understand many inventions. Masters/PhD work might become too theoretical and/or specialized to allow for a broad understanding of the field. If you have a master’s or PhD in a Science or Engineering field, you might still be able to qualify.