Which of the following is most clearly an explanation, rather than an argument?

Group of answer choices

We ought to vacation in Aruba next year because the tickets are cheap.

The sun will rise in the east tomorrow since the earth is spinning eastward.

The right to free speech must be limited$,$ since we would otherwise have to permit slander and incitement of riots.

Since the dodo was a bird, it probably tasted a lot like chicken.

Because of the problems we had with this year$$s Christmas party, we will need to start preparing for next year$$s much earlier.