If \[\overset{\to }{\mathop{p}}\,\] and \[\overset{\to }{\mathop{q}}\,\] are two unit vectors inclined at an angle \[\alpha \] to each other than \[|\overset{\to }{\mathop{p}}\,+\overset{\to }{\mathop{q}}\,|

• A. \[\frac{2\pi }{3}<\alpha <\frac{4\pi }{3}\]
• B. \[\frac{4\pi }{3}<\alpha <2\pi \]
• C. \[0<\alpha <\frac{\pi }{3}\]
• D. \[\alpha =\frac{\pi }{2}\]