"And", "But", and "Or" Get You Very Far

Why is the conjunction in the first line of this story "But" rather than "And" ?

Nearly two-thirds of Minnesotans surveyed think Norm Coleman should concede the U.S. Senate race to Al Franken, but just as many believe the voting system that gave the state its longest running election contest needs improvement.

(a) Because using "But" accurately implies that the majority who think Coleman should concede are offset by another majority who think Franken's victory is somehow tainted by a structurally unsound process.
(b) Because all political reporting must be vested with "balance", whether said "balance" provides a fair, sensible, and/or relevant counterweight to whatever is being reported.
(c) Because writer Kevin Duchschere never saw Schoolhouse Rock and doesn't understand the difference between "And" and "But".
(d) All of the above.

Answers in comments, please.