Assertion $\mid \mathrm{A}$ : If $\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}$ are four points on a semi-circular arc with centre at ' O ' such that $|\overrightarrow{\mathrm{AB}}|=|\overrightarrow{\mathrm{BC}}|=|\overrightarrow{\mathrm{CD}}|$, then $\overrightarrow{\mathrm{AB}}+\overrightarrow{\mathrm{AC}}+\overrightarrow{\mathrm{AD}}=4 \overrightarrow{\mathrm{AO}}+\overrightarrow{\mathrm{OB}}+\overrightarrow{\mathrm{OC}}$ Reason $\mathbf{R}$ : Polygon law of vector addition yields $\overrightarrow{\mathrm{AB}}+\overrightarrow{\mathrm{BC}}+\overrightarrow{\mathrm{CD}}+\overrightarrow{\mathrm{AD}}=2 \overrightarrow{\mathrm{AO}}$

In the light of the above statements, choose the most appropriate answer from the options given below :