Answer:
The correct answer is - It has remained relatively constant since the 1990s.
Step-by-step explanation:
According to the study and research of "Twenty-Five-year Trends in Living Alone in the U.S., 1990 & 2015" the number of data is denoted and plot a graph.
The graph is attached in which all the living alone from 1990 to 2015 including the number of people of age group between 25 to 45 years. It is given that the numbers of particular age groups are relatively constant over the 25 years time period.