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_76 (quantity_preserved VARCHAR, quantity_made VARCHAR, class VARCHAR)
### Question:
What is the quantity preserved when 4 were made of class F-21?
### Answer:
SELECT quantity_preserved FROM table_name_76 WHERE quantity_made = "4" AND class = "f-21"