Final answer:
The state with the smallest percentage of Catholics is California, showing 24.0% in contrast to the higher percentages in the other states listed.
Step-by-step explanation:
According to the data provided, the state with the SMALLEST percentage of Catholics is California, with a percentage of 24.0%. In comparison, the percentages for the other options are: Alabama with 32.2%, Massachusetts known for having a high percentage due to historical migration patterns, and Arizona with 24.3%. The dominance of the Roman Catholic Church in various parts of the United States can be attributed to historical immigration from Europe and more recent Hispanic immigration.