Final answer:
In Australia, the largest religious denomination is Roman Catholic, constituting 22.6% of the population, but Christianity in total accounts for over 50% when all denominations are combined. Option A is correct.
Step-by-step explanation:
The religious group that makes up the majority of the Australian population is Christianity in general, with Roman Catholic being the largest single denomination. According to recent census data, 22.6 percent of the Australian population identifies as Roman Catholic. However, when considering all Christian faiths together, over 29 percent of Australians affiliate with other denominations, taking the total Christian population to more than 50 percent. It is important to note that over 30 percent of Australians report not identifying with any religion. This highlights the secular nature of modern Australian society, as well as its legal framework that ensures freedom of religion and decrees that Australia will have no national religion.