The true statement about plagiarism is: d. Plagiarism is sometimes unintentional. While plagiarism can be intentional, it can also be accidental or unintentional. Unintentional plagiarism can occur when a writer fails to properly cite their sources or unintentionally paraphrases too closely to the original source material. It is important for writers to take steps to avoid unintentional plagiarism, such as carefully citing sources and using plagiarism detection tools to check their work.