Understanding and application

Why are both nouns in بِخُلُقٍ حَسَنٍ genitive?

Conveying Knowledge, Respect, Steadfastness, Taqwa, and Good Character (Hadith 139–145)

• Because both are verbs
• Because an interrogative particle precedes them
• Because bi is a preposition and ḥasan is an agreeing adjective
• Because both are masculine plurals