Explanation:

- Occlude means to block or stop up a passage. It signifies obstruction or preventing something from getting through.

- Option 1: Facilitate means to make a process or action easier or more convenient. It is nearly the opposite of occlude, as it implies aiding progress rather than obstructing it.

- Option 2: Promote means to support or actively encourage a cause, action, or idea. It does not relate to blocking and is more about advancement.

- Option 3: Abstain means to voluntarily choose not to do something. It's about refraining rather than blocking.

- Option 4: Obstruct is a synonym for occlude. It entails the act of blocking or hindering progress or flow.