Final answer:
During the Cultural Revolution, an abstract sculpture of Confucius would be the least understood piece of art as Maoist propaganda sought to remove traditional and 'bourgeois' elements, promoting communist ideology instead.
Step-by-step explanation:
The piece of art that the masses would not understand during the Cultural Revolution is d. An abstract sculpture of Confucius. During the Cultural Revolution, Mao Zedong aimed to eradicate "bourgeois" elements of society and promote communist ideology. Hence, representations that could be associated with feudalism or traditional hierarchies, such as those of Confucius, were often rejected and dismantled. Even when a statue of Confucius appeared in Tiananmen Square in 2011, it was later removed, signifying the ongoing complex views toward Confucian symbols in relation to communist thought. Therefore, any abstract representation of Confucius would have likely been misunderstood or even deemed counter-revolutionary during the Cultural Revolution, unlike the propagandistic art forms promoting Mao or the proletariat.