A
does not address the arguments advanced by the politician’s opponents
The opponents argue “on theoretical grounds” in favor of reducing social spending. The politician fails to show why those theoretical grounds are unpersuasive, or why the opponents’ argument is flawed. This makes the politician’s argument unconvincing.
B
makes an attack on the character of opponents
The politician doesn’t attack the opponents’ character. He criticizes the focus of their argument, but the focus of an argument is not part of one’s character.
C
takes for granted that deficit spending has just one cause
The politician describes the “main cause” of deficit spending. This doesn’t suggest the author believes deficit spending has only one cause. There can be other causes; the politicians identifies what he views to be the main one.
D
portrays opponents’ views as more extreme than they really are
We don’t have any indication that the politician’s description of the opponents’ argument makes the opponents’ position more extreme. All we know is that the opponents’ argument is based on “theoretical grounds.” We don’t know whether this exaggerates the opponents’ position.
E
fails to make clear what counts as excessive spending
The specific level of spending that constitutes “excessive” is not relevant. The opponents argue that there is too much social spending, and the politician responds that we should not reduce social spending. Nothing requires the politician to specify a particular dollar amount.