Thank you for the opportunity to help you with your question!
Here is how the Ames Test works. First of all, it is used for testing with Salmonella, so that gives us the two solutions with Salmonella as part of the answer as options. Next, suspected mutagenic substances are tested for their ability to stimulate backmutations
by placement onto paper discs which are set on the surface of the minimal agar
plates previously inoculated with the auxotroph. The test substance diffuses into the
surrounding media and, if mutagenic, will induce back-mutations which will then allow
growth into visible colonies. The more revertants observed near the test substance,
relative to experimental controls, the more mutagenic the substance is likely to be. Therefore, the answer is "mutagenic in salmonella"
Please let me know if you need any clarification. I'm always happy to answer your questions.