Mathematics

Problem

\vec{a}

\vec{b}

\vec{c}

and

\vec{d}

be the position vectors of the points A, B, C and D respectively, referred to same origin O such that no three of these points are collinear and

\vec{a} + \vec{c} = \vec{b} + \vec{d}

, then quadrilateral ABCD is a a. square b. rhombus c. rectangle d. parallelogram