What keeps the particles of a liquid from spreading out to fill an entire container in the same way that gas particles do?

They are covalently bonded to one another.

They move too quickly to be separated from one another.

The forces of attraction among them limit their motion.

The forces of attraction among them limit their motion.

are you sure

Apologies for the confusion, I made an error in my previous response. The correct answer is:

The forces of attraction among them limit their motion.