Which of the following examples illustrates an imperative mood?

The example "Please close the door" illustrates an imperative mood because it gives a command or request directly to someone. In the imperative mood, the subject is often implied rather than stated explicitly—here, it is understood that the speaker is addressing someone and asking them to perform the action of closing the door.

This construction focuses on urging someone to act, making it a clear indicator of the imperative form. In contrast, the other examples convey statements about actions or desires rather than issuing commands. The use of "please" adds politeness to the command but does not alter its imperative nature. Therefore, this example effectively demonstrates the characteristics of the imperative mood.