When referring to a general degree, use bachelor’s degree and master’s degree.
I received my bachelor’s degree yesterday.
Now, I want to get my master’s degree.
When referring to a specific degree, use Bachelor of and Master of.
I have a Bachelor of Arts degree.
I plan to get a Master of Education degree.
An associate degree is just associate degree—no possessive.
AP convention is to avoid abbreviations if possible.
My friend has a doctorate in education.
If spelling out a degree is too cumbersome, abbreviations, such as B.A., M.A., and Ph.D., are OK. Abbreviations should only be used after a full name, and they should be set off by commas.
Sally Johnson, Ph.D., wrote the textbook.
And just to make matters a little more confusing, keep in mind that AP uses periods with academic degrees (Ph.D.), and APA does not (PhD).