An object at rest cannot remain at rest unless which of the following holds?

If a block is moving to the left at a constant velocity, what can one conclude?

A block of mass $2$kg$2$kg is acted upon by two forces: $3$N$3$N $($directed to the left$)$ and $4$N$4$N $($directed to the right$).$ What can you say about the block's motion?

A massive block is being pulled along a horizontal frictionless surface by a constant horizontal force. The block must be $\_\_\_$

Two forces, of magnitude $4$N$4$N and $10$N$10$N$,$ are applied to an object. The relative direction of the forces is unknown. The net force acting on the object $\_\_\_\_\_\_$