Final answer:
The correct statement about nominal data is that they are categorical. The number of times per week is quantitative discrete data, and the duration is quantitative continuous data.
Step-by-step explanation:
When it comes to the statements about nominal data, the true one is 'b. Nominal data are categorical.' Nominal data are indeed categorical in that they represent categories without any intrinsic ranking. The other statements about nominal data provided in the question are false: nominal data do not have magnitude; they are not a synonym for 'continuous'; and while nominal variables can be dichotomous (having two categories), they are not restricted to only two categories.
For the other questions, the number of times per week is a quantitative discrete data type, because it is the result of counting and takes on specific numerical values. The duration (amount of time) is a quantitative continuous data type because it is the result of measuring and can take on any value within a range.