A、<p><span style="font-family: 微软雅黑, 'Microsoft YaHei';">1</span><br></p>
B、<p><span style="font-family: 微软雅黑, 'Microsoft YaHei';">0</span><br></p>
C、<p><span style="font-family: 微软雅黑, 'Microsoft YaHei';">-1</span><br></p>
D、<p><img class="kfformula" src="data:image/png;base64,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" data-latex="-\frac {1} {2}"></p>