This is the best answer. P1 describes Maoist Revolutionary Realism and the political and artistic ideas of it. These ideas influenced Scar Art and Native Soil, which are discussed later in the passage. (Scar Art and Native Soil “flourished in reaction to the monotony of Revolutionary Realism.”)

There’s no support for the “inescapable melding” of anything. That language is too extreme; the author never suggests anything was “inescapable.” We have no idea what would have happened if the Cultural Revolution didn’t occur; would political ideas and artistic styles have melded? We don’t know.

P1 doesn’t explain changes in Chinese society. It explains how the Cultural Revolution intensified Maoist Revolutionary Realism. But we don’t get any description of how society changed during the Cultural Revolution.

The author doesn’t refute anything in P1. P1 presents part of the author’s own argument concerning the effects of the Cultural Revolution on Chinese art.

It’s not clear that Scar Art or Native Soil practiced “political realism.” Maoist Revolutionary Realism was “political realism” in that it portrayed reality that was colored and distorted by political ideology. But this is a different kind of realism from that practiced by Scar Art and Native Soil.