Final answer:
The Solar Neutrino Problem was solved by the discovery of neutrino oscillations, where neutrinos change flavors during their journey from the Sun to Earth, explaining why fewer electron neutrinos were detected than expected. The correct option is A.
Step-by-step explanation:
The Solar Neutrino Problem was eventually solved by the discovery that neutrinos change flavors on their journey from the Sun to Earth, a process known as neutrino oscillation.
This phenomenon was confirmed by various experiments, including the Sudbury Neutrino Observatory, which detected neutrinos changing from electron neutrinos (the type produced in the solar core) to other flavors, such as muon neutrinos.
This effectively explained why earlier experiments detected only about one-third the number of neutrinos expected based on models of the solar core, as those detectors were designed specifically to detect electron neutrinos.
The correct answer to the student's question is: a) Neutrinos were found to change flavor during their journey. Subsequent research has also indicated that neutrinos have a small amount of mass, which is necessary for the oscillation process to occur.
This solution not only explained the discrepancy in neutrino detection but also provided insights into the properties of neutrinos and their role in both solar physics and the broader cosmic context. The correct option is A.