To what extent is oil pollution the worst impact of marine debris and death of coral reefs?

Most coral reefs occur in shallow water near shore. As a result, they are particularly vulnerable to the effects of human activities, both through direct exploitation of reef resources, and through indirect impacts from adjacent human activities on land and in the coastal zone. Many of the human activities that degrade coral reefs are inextricably woven into the social, cultural, and economic fabric of regional coastal communities.

Coral reefs face many threats from local sources.

Hope this helped

C.about 10% i think