The two correct answers are:
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if the original work is under a Creative Commons license - Many Creative Commons licenses require attribution to the original creator when using their work.
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if the original work is copyrighted - Attribution is generally required when using copyrighted works, especially if the use does not fall under fair use exceptions.
The other options do not necessarily require attribution based on the conditions provided. For example, works in the public domain do not require attribution, and making changes to the original work does not inherently necessitate attribution unless specified by a license.