The correct answer is two-party system
Two-party System is the political structure in which two major parties compete for power. This type of system means that minority parties are excluded.
With two-party system, one part accedes to the government obtaining the majority of the votes, while another part becomes the official opposition reaching the second place in the voters' preferences. The remaining parts, on the other hand, are left without legislative representation or with very limited representation.
The existence of two-party system means that the two main political coalitions receive all the attention of the media and monopolize the political debate. As a consequence, the other political expressions do not gain space to spread their ideas and communicate their proposals. By extension, at election time, smaller parties receive few votes and, thus, the bipartisan system is perpetuated.
In general, two-party system opposes two antagonistic political positions, as liberal against conservatives or left against right. In any case, it is now common for party ideologies to be less rigorous and for all coalitions to end up competing for the same voter.
