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_86 (date VARCHAR, time VARCHAR, meet VARCHAR, nationality VARCHAR)
### Question:
What is Date, when Meet is "World Championships", when Nationality is "United States", and when Time is "1:46.68"?
### Answer:
SELECT date FROM table_name_86 WHERE meet = "world championships" AND nationality = "united states" AND time = "1:46.68"