Select the best word for the blank in the following sentence: '_______ is my favorite black dress.'

The correct answer is 'That.' In the sentence, 'That is my favorite black dress,' 'That' is used to refer to a singular object that is close in proximity. 'This here' is colloquial and not suitable for formal writing, making it incorrect in this context. 'Those' is plural and does not agree with the singular noun 'dress.' 'Where' is used to denote a location or position, which is not suitable for describing a dress. Therefore, 'That' is the most appropriate word choice to complete the sentence.