Solve \[{{\left( \mathbf{a}+\mathbf{b} \right)}^{\mathbf{2}}}-{{\left( \mathbf{a}-\mathbf{b} \right)}^{\mathbf{2}}}\]

• A. \[2ab\]
• B. \[{{a}^{2}}+{{b}^{2}}\]
• C. \[2{{a}^{2}}+2{{b}^{2}}\]
• D. \[4ab\]