A matched-pairs t-interval is NOT an appropriate way to analyze data consisting of which of the following?

Measurements of annual income for both individuals in pairs formed by matching 100 people from State A and 100 people from State B based on level of education

Measurements of annual income recorded for both spouses of 100 randomly selected married couples

Measurements of annual income for each twin for 100 randomly selected pairs of twins

Measurements of annual income taken both before and after a two-year training course for a random sample of 100 people who took the course

Measurements of annual income for both individuals in pairs formed by assigning 100 people to pairs at random