They promoted social, economic and political reform, by protesting, lobbying and changing laws.
Based on Teddy Roosevelt's quote "We draw the line against misconduct, not against wealth," the option that explains his position is C. because trusts are not all bad, only those trusts which employ practices that do not benefit the public as a whole should be abolished. Roosevelt did not oppose the accumulation of wealth, but he did oppose the improper use of that wealth when it negatively impacted society overall as was the case with many trusts and monopolies in the late 19th and early 20th centuries (and in some cases today).
An interest group (also called an advocacy group, lobbying group,
pressure group, or special interest) is a group, however loosely or
tightly organized, that is determined to encourage or prevent changes in
public policy without trying to be elected.
So based off this knowledge, we can eliminate C. :)
I don't think it's A or B because they are more concerned with change
and advocacy than a "free time" thing.
So going with this definition, I'd go with D ;)