user: Question: Which Class has a Frequency MHz larger than 91.7, and a Call sign of K272EC?
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'Class', 'FCC info']
Types: ['text', 'real', 'text', 'real', 'text', 'text']
Sample row: ['K201ER', 88.1, 'Holbrook, Arizona', 50.0, 'D', 'FCC']
SQL:

assistant: SELECT "Class" FROM "Table" WHERE "Frequency MHz" > 91.7 AND "Call sign" = 'K272EC';