The sentence that uses direct address is "Where are you going, Fred?".
Direct address in grammar means that you are speaking directly to a person or group of people either calling them by name, as in example, "Where are you going Fred?", or using the second person pronoun "you". As in the example above, the name is often separated from the rest of the sentence or question by a comma. For example, "Maria, I need you to finish your homework now."
