The length of the common chord of the circles \[{{(x-a)}^{2}}+{{(y-b)}^{2}}={{c}^{2}}\]and \[{{(x-b)}^{2}}+{{(y-a)}^{2}}={{c}^{2}}\], is

• A. \[\sqrt{4{{c}^{2}}-2{{(a-b)}^{2}}}\]
• B. \[\sqrt{4{{c}^{2}}+2{{(a-b)}^{2}}}\]
• C. \[\sqrt{4{{c}^{2}}-2{{(a+b)}^{2}}}\]
• D. \[\sqrt{4{{c}^{2}}+2{{(a+b)}^{2}}}\]