Final answer:
The Australian Constitution came into effect on January 1, 1901, when Australia's colonies united under a federal system as the Commonwealth of Australia.
Step-by-step explanation:
You asked about the Australian Constitution, specifically when it took effect. The correct answer is a) 1901. The Australian Constitution took effect on January 1, 1901, when the colonies of Australia united to form the Commonwealth of Australia, a federal system of government. While each state retained its individual legislative powers, it was also governed by the federal Constitution and parliament. Although the British monarch was recognized as the ceremonial head of state, Australia had its own democratically elected government. The Australian Constitution took effect on January 1, 1901, marking a significant milestone in the nation's history. This constitutional framework united the separate colonies into the Commonwealth of Australia, forming a federal government with shared powers between the states and the central authority. The year 1901 symbolizes Australia's transition from a collection of independent colonies to a federated nation. The Constitution outlines the structure of government, the distribution of powers, and the principles guiding the new Commonwealth. Amendments, such as the 1967 referendum, were later made to address Indigenous rights, but the foundational legal framework was established in 1901, shaping Australia's political and legal landscape.