Final answer:
The ultimate cause of the cholera outbreak at Golden Square was sewage-contaminated water at the Broad Street Pump, discovered by Dr. John Snow's investigative work.
Step-by-step explanation:
The ultimate cause of the Cholera outbreak in Golden Square, London was indeed contaminated water at the Broad Street Pump. Investigations by Dr. John Snow during the cholera epidemic of 1854 highlighted the dangers of sewage-contaminated water and contributed significantly to the field of epidemiology.
Snow’s mapping and data collection led to the revelation that the water source for the Broad Street pump was tainted by sewage, which convinced local authorities at the time to shut down the pump. This act helped reduce the number of cholera-related deaths dramatically. Later on, Snow's work inspired crucial improvements in public health and the overhaul of London's water and waste systems, thus preventing further outbreaks.