> {} ****
Should be the correct answer. Sō da is an auxiliary na-adjective, and when used to describe a noun, the prenominal form sōna should be used.
Other option is to use, for example when talking about a plate of apples:
> (Which apple you ate?)
>
> **** (I've ate the looking good one [apple])
When using the particle , the whole pharse before it acts like a noun: (The looking good one) . So it can be used with .