What is the contextual sense of bayḍati khidrin in verse 23?

Imruʾ al-Qays: A Guarded Tent, the Pleiades, Objection, and Dunes (Verses 23–29)

• A figurative picture of a protected, secluded woman
• Only the whiteness of the tent, without reference to a woman
• A story about guarding an actual bird egg
• Only the color of clothing with no idea of seclusion