What is the call sign for a class of A?
CREATE TABLE table_52308 (
    "Call sign" text,
    "Frequency MHz" real,
    "City of license" text,
    "ERP W" real,
    "Class" text,
    "FCC info" text
)
SELECT "Call sign" FROM table_52308 WHERE "Class" = 'a'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the call sign for a class of A? ### Input: CREATE TABLE table_52308 (
    "Call sign" text,
    "Frequency MHz" real,
    "City of license" text,
    "ERP W" real,
    "Class" text,
    "FCC info" text
) ### Response: SELECT "Call sign" FROM table_52308 WHERE "Class" = 'a'