Why Should President Obama and His Advisors Not Have Been

Why should President Obama and his advisors not have been surprised by Mitt Romney's changing positions as he began campaigning during the general election?

A) Candidates must court a broader national electorate in a general election, which requires shifts in a candidate's tone, emphasis, and even policy positions.
B) Candidates must rally their party faithful during the general election, which requires shifting positions on key issues to continue to win the support of the party.
C) Candidates recognize that the voters in general elections are much more ideological than those in primaries, so they must shift their policy positions to accommodate this orientation.
D) Candidates are seldom sure of their policy positions during primary elections and often shift and change positions until they establish their views during the general election.