唯物辯證法的實(shí)質(zhì)和核心是:A. 聯(lián)系的觀點(diǎn)B. 發(fā)展的觀點(diǎn)C. 對(duì)立統(tǒng)一規(guī)律D. 質(zhì)量互變規(guī)律