Final answer:
Trade disruptions was a significant economic factor contributing to the decline of the Byzantine Empire.
Step-by-step explanation:
A significant economic factor that contributed to the decline of the Byzantine Empire was a) Trade disruptions.
Trade disruptions occurred as a result of invasions by Persians and Arabs in the seventh century. These invasions led to the loss of territories and a decline in trade, which caused an economic downturn. The empire faced challenges in maintaining its trade networks, and this contributed to its decline.