B: self-perception theory doesn't maintain that an uncomfortable state of tension is aroused when attitudes and actions are inconsistent

    Correct.
Self-perception is defined by Myers (pg 157) as "the theory that when unsure of our attitudes, we infer them much as would someone observing us-- by looking at our behavior and the circumstances under which it occurs."  Self-perception does not ever deal with internal tension at all.  Because this is a major difference between the two theories, with cognitive dissonance theory maintaining that there is internal tension, answer B is correct.