Which of the following is a concrete message?

A. "When is she coming home?" This is a specific question but lacks concrete details. It is an open-ended query that may not be as precise as a concrete message. B. "Help me put this pile of books on Marsha's desk" This is a concrete message because it provides specific instructions and clear action steps. C. "Get this out of here": This is an ambiguous message that lacks clarity and specific details about what needs to be removed and where it should go. D. "They said it is too early to get in.": This message is somewhat vague and lacks specific details about who "they" are and what "get in" refers to.