Since jessica's participation in local politics increased significantly after she joined her school's political science club, it is clear that her involvement in that club led her to take an interest in politics. the argument above is flawed because:

The correct answer is: it is possible that an interest in politics caused Jessica to join the political science club.

The argument in the question is flawed because it automatically assumes that Jessica's involvement in her school's political science club led her to take an interest in politics, rather than the other way round, when in fact it is possible that an interest in politics is what actually caused Jessica to join the political science club. The argument in the question is flawed because it made a causal claim simply by an unfounded assumption. 

The repetition of initial consonant sounds is called alliteration