The phrase "The Bee's Knees" is an idiomatic expression that originated in the 1920s. It is used to describe something or someone as excellent, outstanding, or exceptional. The phrase is believed to have been coined during the Jazz Age, a time when new and fashionable expressions were popular. Comparing something to the knees of a bee, which are tiny and precise, implies that it is the best or most desirable. Therefore, the correct answer is "a compliment for a wonderful person or thing."