US universities have a common standard:
1. A Master's student must maintain a GPA of 3.0 to graduate.
2. In A, B, C, D, F grading system and 3 credits:
A=3x4=12; B=3x3=9; C=3x2=6; D=3x1=3; F=3x0=0
Do some maths and find your GPA.
3. The first time you get a C and your GPA is below 3.0, you get academic warning
* Your assistantship is taken away
* You are on acadmic probation or watch
4. The second semestr you are below 3.0 GPA, you are in academic suspension. You can't further enroll to new course, but you have to go through remedial process.
5. Some universities prefer to disassociate with you after step 4.
6. After you in step 3, just start looking a fourth-tier college for you next possible transfer. Google US News for Ranking of US Colleges and Universities.