What is the production code of the episode written by Cathryn Humphris?
CREATE TABLE table_24938621_3 (production_code VARCHAR, written_by VARCHAR)
SELECT production_code FROM table_24938621_3 WHERE written_by = "Cathryn Humphris"
<s>[INST] Write mssql query to answer the following question given the database schema. Schema: CREATE TABLE table_24938621_3 (production_code VARCHAR, written_by VARCHAR) Question: What is the production code of the episode written by Cathryn Humphris? [/INST] SELECT production_code FROM table_24938621_3 WHERE written_by = "Cathryn Humphris" </s>