a
(a) \(\mathop {H - \mathop {\mathop C\limits^| }\limits^H = \mathop {\mathop C\limits^| }\limits^H - \mathop {\mathop {\mathop {\mathop C\limits_| }\limits_H }\limits^| }\limits^H - C \equiv \mathop {\mathop C\limits^| }\limits^H }\limits_{10\sigma \,\,\,\,\,\,\,3\pi } \)