One reason for the rise of public interest groups in the 1960s and 1970s was a. the decline in political parties b. americans' growing cynicism about government during the vietnam war c. the lifting of legal restrictions on lobbying activities d. technological developments that made interest group activities easier

B) Americans' growing cynicism about government during the Vietnam War

Explanation:

The American people started to doubt many of the actions that the government was taking during the Vietnam war because they believed many of those were just propaganda to make the government look as the good ones, but the people knew of some of the horrific acts they were doing in Vietnam.

answer; 5% is your answer; ///good luck