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 you're looking for sushi, the restaurant in front of the station is good.
Explanation
なら takes up sushi as the topic and gives advice about it: 寿司なら means 'if we're talking about sushi.' A form such as 寿司だったら is also grammatical, but なら is the direct topic-taking conditional used here.