In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: RESULTS : A sustained virological response ( SVR ) was 29 . 6 % ( 8 / 27 ) in group A and 10 % ( 1 / 10 ) in group B , respectively .
### Output Text:
RESULTS : A sustained virological response ( SVR ) was 29 . 6 % ( 8 / 27 ) in group A and 10 % ( 1 / 10 ) in group B , respectively . 