Why Did the Whig Party Eventually Collapse

Why did the Whig party eventually collapse?

A) It no longer had sufficient numbers of people voting for it because it was entirely at odds with the Republican Party.
B) It opposed slavery to such a degree that it lost all support among southern voters and could not recover.
C) The strain of the Kansas-Nebraska Act pushed northern and southern members toward joining different parties.
D) The Republican party successfully defeated the major Whig candidates in the 1852 election.
E) Its economic policies were perceived as too socialist considering the recent onset of a major depression.