Answer:
A. Encouraging citizens to vote.
Step-by-step explanation:
The political parties play a considerable and significant role during elections as they encourage the civilians to use their right to vote. They visit from locality to locality in order to aware them about voting and inspire them to vote in as much number as possible. However, they may do it selfishly to acquire more votes for their party yet leaving the reason, if the actions are to be considered, then they are quite helpful during the elections. The newly become adults are granted with their voter identity cards and made aware of the voting procedure. Thus, the most important role the political parties play is "encouraging citizens to vote". The other options come secondary to this one.