\( \mathrm{ABCDEF} \) is a regular hexagon. The centre of hexagon i...

\( \mathrm{ABCDEF} \) is a regular hexagon. The centre of hexagon is a point \( \mathrm{O} \). Then the value of \( \overrightarrow{\mathrm{AB}}+\overrightarrow{\mathrm{AC}}+\overrightarrow{\mathrm{AD}}+\overrightarrow{\mathrm{AE}}+\overrightarrow{\mathrm{AF}} \) is
(a) \( 2 \overrightarrow{\mathrm{AO}} \)
(b) \( 4 \overrightarrow{\mathrm{AO}} \)
(c) \( 6 \overrightarrow{\mathrm{AO}} \)
(d) Zero
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