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 (quantity INTEGER, type VARCHAR, retired VARCHAR)
### Question:
What is the lowest quantity of the 1b n2 type, which was retired in 1907-12?
### Answer:
SELECT MIN(quantity) FROM table_name_50 WHERE type = "1b n2" AND retired = "1907-12"