First, please note that different texts may use the term "political" differently and so our answers here may not be the same as what your book or instructor would say. I would suggest that you check your notes and/or your book.
That said, social movements are definitely political movements. Politics may be defined as the process of transmitting the wants of the people (including groups of people) to government. We should also note that politics involves trying to help influence the actions of governmental officials and the policies that those officials enact.
Using this definition, a social movement is clearly a political movement. Social movements are transmitting the wants of the kind of people who make them up. They are trying to influence the government to enact policies that will be beneficial to those people.
Of course, social movements tend to be unorthodox and tend not to use established political channels such as voting and lobbying. Nonetheless, their goals make them political movements.