All calculations are permitted on what type of data?

A) Interval data
B) Nominal data
C) Ordinal data
D) All of these choices are true.

Calculations are permitted on interval data, which is a type of numerical data where the intervals between values are equal. Nominal data is categorical data where values are simply named or labeled, while ordinal data is also categorical data, but the values have a natural ordering. While calculations may be possible with some types of ordinal data, such as calculating medians or percentiles, they are not as widely used as with interval data. Therefore, the best choice is A, interval data.