In which one of the following metal carbonyls, CO forms a bridge between metal atoms?
\( \mathrm{[Os_3(CO)_{12}]} \)
\( \mathrm{[Ru_3(CO)_{12}]} \)
\( \mathrm{[Mn_2(CO)_{10}]} \)
\( \mathrm{[Co_2(CO)_8]} \)