* Deg.: A short and widely understood abbreviation for "degree."
* B.A./B.Sc./B.S.: If you know it's a Bachelor's degree, you can use the appropriate abbreviation depending on the field (Arts, Science).
* M.A./M.Sc./M.S.: Similar for a Master's degree.
If possible, it's always better to specify the type of degree (Bachelor of Arts, Master of Science, etc.) rather than using a general abbreviation. Using a general abbreviation might lead to ambiguity.