How does the supplied commentary explain the Qiblah “direction” for a person who cannot see the Ka'bah?

Conditions of Prayer Part 2: Facing the Qiblah (استقبال القبلة)

• Any direction chosen for convenience.
• The side which aligns the worshipper with the Ka'bah or its airspace.
• Only the direction of the nearest mosque door.
• The direction of sunrise in every place.