Final answer:
Cyclone Tracy hit Darwin in the year 1974, causing widespread destruction and leading to a significant reconstruction effort.
Step-by-step explanation:
Cyclone Tracy was a significant natural disaster that had a profound impact on Australia when it struck the city of Darwin. The correct answer to your question is a) 1974. On Christmas Eve of 1974, Darwin was devastated by the powerful Cyclone Tracy, which destroyed more than 70% of the city's buildings, including 80% of houses, and resulted in the evacuation of over 30,000 people. The cleanup and reconstruction efforts in the aftermath highlight the resilience and community spirit of Darwin's residents during this challenging time.