Read the following sentences: There isn’t anything to eat in the house. Let’s order a pizza.

Which revision below is a complex sentence?

There isn’t anything to eat in the house, so let’s order a pizza.

Since there isn’t anything to eat in the house, let’s order a pizza.

Because there isn’t anything in the house, let’s order a pizza, so we’ll have something to eat.

Let’s order a pizza; there isn't anything to eat in the house