For the illustrator to use the photographs in his digital collage for a paid commission, he should look for Creative Commons licenses that allow for commercial use and adaptations of the work. The two correct answers would be:
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CC BY (Creative Commons Attribution) - This license allows for both commercial use and adaptations as long as the original creator is credited.
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CC0 (Creative Commons Zero) - This license allows for any use, including commercial and adaptations, with no requirement for attribution.
The other options (CC BY-ND, CC BY-NC-ND, and CC BY-NC-SA) have restrictions that do not allow for commercial use or adaptations.