Fill in the blank with the correct article.
Imitation is ______ sincerest form of flattery.

- A definite article is an article that is used to make a noun definite or particular.
- Article 'The' is used to make any noun definite. It can be used with a singular as well as a plural noun.
- Article 'the' is also used before the superlative degree of an adjective.
- Example: This is the most precious metal.
- Since 'sincerest' is the superlative degree, therefore, 'the' will be used in the blank.