I, @lturner, being of a foraging mind today, choose Option 1

• I have 1 Knife
• I must eat by the End of Day 2 to avoid starvation

It's highly possible to find food in that abandoned lot. Not so highly possible in the other two options, besides which I'm concerned about the sewers having been backed up for 2 months. It seems like any scraps you might find in the store carry a high likelihood of contamination. The cars are a slightly better prospect, but it's been high looting time in the city and cars have got to be pretty well picked over. My guess is you may find other inventory in the store or the cars, but food is a fainter prospect and right now you don't know if there is a possibility of food during the rest of the day. If there isn't, anyone who doesn't find food now has a really high chance of being eliminated in the next round. (Higher than usual, that is!)