Which sentence correctly uses a modal to express a strong obligation?
กStaff might wear identification badges in the secure area.
ขStaff must wear identification badges in the secure area.
คStaff could have worn identification badges in the secure area.
งStaff would wearing identification badges in the secure area.
เฉลยอธิบาย
must แสดงข้อบังคับที่ชัดเจน