寿司___、駅前の店がおいしいですよ。
Q. Which conditional means 'if it's sushi (you're talking about)...'?
Translation
If it's sushi you want, the place in front of the station is good.
Explanation
なら takes up something just mentioned as a topic and gives advice about it: 寿司なら 'if we're talking about sushi'. たら/ば/と need a verb, and none carries this 'as for that topic' nuance.