Mountain County and Sunrise County are two comparable counties, with similar numbers of registered voters. Both are in the same region of the state. In both counties, about 60% of the registered voters are registered Republicans, and almost all others are registered Democrats. In 2005, Republican candidate Alf Landon ran for supervisor of Mountain County, and Republican candidate Thomas Dewey ran for supervisor of Sunrise County. Both took similar stands on issues, and both ran against conservative Democratic candidates in the general county-wide election, and none of these four candidates was an incumbent at the time of this election. The Republican Congressman representing Sunrise County endorsed Mr. Dewey, but the Republican Congressman representing Mountain County refrained from endorsing Mr. Landon. Mr. Dewey won his election, but Mr. Landon lost his election. Clearly, the endorsement positions of the respective Congressmen were the deciding factors in these elections.

In evaluating the argument, it would be most useful to know which of the following?

A:How these two counties have voted in US Congressional and US Presidential elections over the past decade.

B:What stands Mr. Landon and Mr. Dewey took on issues considered most important by registered Democrat voters

C:How well Congressmen, involved primarily in national politics, are informed of the details of local politics within a single county.

D:How typical it has been throughout the state, in the past decade, for a Congressman to endorse a county supervisor candidate running in his Congressional district.

E:How many voters in each of these two counties were aware of their respective Congressman's endorsement positions.