Examine this statement, which executes successfully:Now examine this query:Which two statements can do this?

ALTER TABLE employees -

ADD INDEX (birth_date DESC);

ALTER TABLE employees -

ADD INDEX ((MONTH(birth_date)));

ALTER TABLE employees -

ADD COLUMN birth_month tinyint unsigned GENERATED ALWAYS AS (MONTH(birth_date)) VIRTUAL NOT NULL,

ADD INDEX (birth_month);

ALTER TABLE employees -

ADD COLUMN birth_month tinyint unsigned GENERATED ALWAYS AS (birth_date->>'$.month') VIRTUAL NOT NULL,

ADD INDEX (birth_month);

ALTER TABLE employees -

ADD INDEX ((CAST(birth_date->>'$.month' AS unsigned)));

ALTER TABLE employees -

ADD INDEX (birth_date);