己知：$HCN\left(aq\right)$与$NaOH\left(aq\right)$反应的$△H=-12.1KJ/mol$；$HCN\left(aq\right)$与$NaOH\left(aq\right)$反应的$△H=-55.6KJ/mol$。则$HCN$在水溶液中电离的$△H$等于

A．	$-67.7KJ/mol$	B．	$-43.5KJ/mol$
C．	$+43.5KJ/mol$	D．	$+67.7KJ/mol$