What is true about both sodium and gold?
a)they are volatile.
b)they are very reactive.
c)they are in the same group.
d)they are metals.

Generally speaking, gold is not very reactive, whereas sodium is highly reactive. They are most definitely not in the same group since sodium is in group 1 and Gold is in group 11. Gold is indeed a transition metal so my best guess would be D. 

Answer; carbon monoxide (co);