Thanks to her high grades at university, she is offered the position.

• A. 
  If she had not got high grades at university, she would not be offered the position.
• B. 
  It was her high grades at university which offer her the position.
• C. 
  If she had not got high grades at university, she would not have been offered the position.
• D. 
  Without her high grades at university, she is not offered the position.