The response that most closely explains what Margaret Hamilton meant by the statement, “It’s like preventative healthcare, but preventative software,” is:
While a root canal can be performed by a dentist, there are also steps that could be taken to prevent its necessity. Similarly, there are steps that can be taken to prevent errors and issues due to poorly engineered software.
This response draws a parallel between preventative healthcare practices that reduce the likelihood of needing medical interventions and preventive measures in software engineering that aim to avoid errors and issues.