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_1 (call_sign VARCHAR, class VARCHAR, frequency_mhz VARCHAR)
### Question:
Which call sign has a Class of A, and a Frequency MHz of 88.7?
### Answer:
SELECT call_sign FROM table_name_1 WHERE class = "a" AND frequency_mhz = 88.7