【单选题】

TheAmerican party system is a two-party system which is unlikely to become anything else. It is not just that the two-party polarization has the weight of tradition behind it but also that the two-party polarization is built into our constitutional and legal system. Our entire electoral arrangements, the absence of proportional representation, the exorbitant cost of political campaigns, the legal difficulties in getting on and staying on the ballot in many states-all these things work against the rise of minor parties.

Also the single member legislative district, the division of power between the nation and the states, the method of electing a president with the winner itself, work to keep power in the hands of the two major parties. Major parties (like the Federalists and the Whigs) have broken up and been replaced as new parties have emerged in the past.But no minor party has ever gradually risen to achieve the stature of a major party, and no third party has lasted very long in any prominent capacity.
All this is not to say that third parties do not have a function in theAmerican system. However, their function is largely that of pressure groups, and in this respect they are a curious combination ofEuropean special-interest parties andAmerican interest groups. They have at various times been useful in bringing to the fore the interests of neglected groups in the public at large. The Populist party of 1890’s as was a notable case in point.
What happens characteristically, however, is that as soon as third parties begin to make their mark, one or both of the major parties appropriates enough of their principles or program to absorb the discontent on which they were flourishing. For this reason it has been said that third parties are like bees: once they have stung they must die.
It can be inferred from this passage that ______ .
A、traditional power supports the two-party system in the United States
B．none of the major parties has broken up in the past
C．Populist party was the only third party inAmerica
D．the function of third parties is support the two-party system