Two forces \[{{\vec{F}}_{1}}=10\hat{i}-\hat{j}-15\hat{k}\] and \[{{\vec{F}}_{2}}=10\hat{i}-\hat{j}-15\hat{k}\] act on a single point. The angle between \[{{\vec{F}}_{1}}\] and \[{{\vec{F}}_{2}}\] is nearly

• A. \[{{30}^{o}}\]
• B. \[{{45}^{o}}\]
• C. \[{{60}^{o}}\]
• D. \[{{90}^{o}}\]