Final answer:
Control variables for comparing green cleaners to store-bought cleaners are C) Cleaning effectiveness and ingredients to ensure a fair comparison and to evaluate their performance and environmental impact.
Step-by-step explanation:
When comparing green cleaners to store-bought cleaners, the control variables that should be considered are C) Cleaning effectiveness and ingredients. These factors ensure that the comparison between the two types of cleaners is fair and unbiased. Control variables such as cleaning effectiveness are essential to determine the actual performance of the cleaners in removing dirt, grime, or stains appropriately. Moreover, examining the ingredients is vital for comparing the environmental and health impacts, aligning closely with the green cleaners' proposition of being eco-friendly. Aspects like color and fragrance, although part of the sensory experience of the cleaning product, are less critical to the cleaner's intended function and mainly affect consumer preferences.