He/ better/ not go/ school/ because/ feel unwell//

• A. 
  He'd better not to go to school because he is feeling unwell.
• B. 
  He'd better to not go to school because of his feeling unwell.
• C. 
  He'd better not going to school because he was feeling unwell.
• D. 
  He'd better not go to school because he is feeling unwell.