Questions: Plagiarism is attributing a quote to multiple sources. failing to give proper credit to others for their ideas and words. always unintentional. only a problem when it is intentional.

The answer is: failing to give proper credit to others for their ideas and words.

Explanation for each option:

1. Attributing a quote to multiple sources: This is incorrect. While attributing a quote to multiple sources might be confusing or incorrect, it is not the definition of plagiarism. Plagiarism specifically involves using someone else's work without proper attribution.

2. Failing to give proper credit to others for their ideas and words: This is correct. Plagiarism is defined as using someone else's ideas, words, or work without giving them proper credit. This can include copying text, paraphrasing without acknowledgment, or presenting someone else's work as your own.

3. Always unintentional: This is incorrect. Plagiarism can be both intentional and unintentional. Intentional plagiarism involves knowingly presenting someone else's work as your own, while unintentional plagiarism might occur due to a lack of understanding of proper citation practices.

4. Only a problem when it is intentional: This is incorrect. Plagiarism is a problem regardless of intent. Even if it is unintentional, it still constitutes a breach of academic integrity and can have serious consequences. Proper citation and acknowledgment are essential to avoid plagiarism.