وَمَا هُمْ عَنْهَا بِغَآئِبِينَ ۝١٦ What does the extra emphatic بِ do in بِغَآئِبِينَ?

Surah Al-Infitar — Part 3

• It makes the word nominative
• It makes a verb jussive
• It makes the word accusative
• It makes the predicate genitive in form