Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_50 (erp_w VARCHAR, class VARCHAR, call_sign VARCHAR)
### Question:
Which ERP W has a Class of A, and a Call sign of wffc?
### Answer:
SELECT erp_w FROM table_name_50 WHERE class = "a" AND call_sign = "wffc"