Find $\int _ { C } \vec { F } \cdot d \vec { r }$

Multiple Choice

Find $\int _ { C } \vec { F } \cdot d \vec { r }$ of the function over the given curve: $\vec { F } ( x , y ) = \langle x , y \rangle$ and the curve C is given by $\vec { r } ( t ) = \langle \cos ( t ) , \sin ( t ) \rangle , 0 \leq t \leq \frac { \pi } { 2 }$

A) $\frac { 1 } { 2 }$
B) $0$
C) $- 1$
D) $\pi - 1$