This diagram shows the sectionary box sitting on the floor which statement about other force exerted on the box are true? questions:

it's normal force exerted by the floor. it balances the gravitational force.

it's friction force exerted by the floor. it balances the gravitational force.

it's normal for exerted by the floor. does not balance the gravitational force.

it's an applied force exerted from the left. It doesn't balance the gravitational force.

A) It's a normal force exerted by the floor. It balances out the gravitational force.

The normal force pushes up which means the box doesn't go through the floor. The up and down forces are balance. If the normal force was larger than the gravitational force, then the box would be pushed up and float/jump in the air. But the box is stationary and not moving, so that's why we don't have any acceleration and the forces effectively cancel each other out. In a way you can think of it like a see-saw.

Friction would only come into play if you applied a force and were trying to move the box. Friction counteracts the applied force. If you push the box to the left, then the friction would push to the right. Friction slows down the box and it allows it to not slide forever.