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_3 (callsign VARCHAR, commenced_operations INTEGER)
### Question:
Who is the call sign that has a commenced operation before 1976?
### Answer:
SELECT callsign FROM table_name_3 WHERE commenced_operations < 1976