This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to keep dog food fresh
Open the bag carefully.
Many dog food bags are made to have food stored directly in them. Open the bag carefully along the top seam or dotted line so that you can fold and roll the bag later.

Choices:
[1]. If the bag comes with a zipped top, open carefully above the seal to keep it intact for later. Use scissors or a knife to get a clean, consistent opening from the bag.;
[2]. Some bags may be large enough for several dogs, but others will be small enough that no one can fit in without touching them. Whether you use one of the natural or homemade baggies, you should make sure that the bag will allow your dog to eat without interrupting its appetite.;
[3]. Place your choice of treat into the bag. You will need at least a handful of your chosen treat for maximum freshness.;
[4]. Let the food drip out easily, then transfer it to a container that will catch the drip. There should not be any air left in the bag, as fresh dog food is spread out easily in a landfill.;
The answer is:
[1].