user: Question: Name the class with call sign of K220CP
Columns: ['Call sign', 'Frequency MHz', 'City of license', 'ERP W', 'Class', 'FCC info']
Types: ['text', 'real', 'text', 'real', 'text', 'text']
Sample row: ['K201BM', 88.1, 'Canadian, Texas', 74.0, 'D', 'FCC']
SQL:

assistant: SELECT "Class" FROM "Table" WHERE "Call sign" = 'K220CP';