Final answer:
Daisy would likely have reacted defensively or with discomfort to Nick's sharp questioning, becoming evasive or offended, and it could have strained their relationship.
Step-by-step explanation:
If Nick had not "reserved judgment" and instead questioned Daisy sharply regarding Tom’s mistress or her apparent agreement with Tom’s theories about the “rise of the colored empires,” it is likely that Daisy would have reacted defensively or with discomfort. Given her character as established in The Great Gatsby, a direct confrontation might have led her to become evasive, as she tends to avoid unpleasant truths and retreats into her social status and comfort. It is also possible that she would have been offended or shocked by Nick's bluntness, considering that such a questioning would break the social etiquette and the indirect manner of communication typically found in her circle. Daisy's reactions in the novel to various situations suggest that a straightforward questioning by Nick would have been both unexpected and unwelcome, potentially straining their relationship.