Final answer:
The description of the Priest's mantle or Kesa from the 18th century would be both silk brocade and gold and silver thread.
Step-by-step explanation:
The description of the Priest's mantle or Kesa from the 18th century would be both A and B. The mantle would typically be made of silk brocade, which is a richly decorative fabric with a raised design woven into it. It would also often be adorned with gold and silver thread, adding a touch of luxury and prestige to the garment.