A. the lack of clear rules governing it
B. the lack of government’s support of exploiting it
C. the poor prospect of exploiting it
D. the lack of commercial interests of pursuing it

A. They have started their marine bio-prospecting on deep-sea level.
B. They didn’t take any action on the marine bio-prospecting.
C. They have already focused on it but had not begun to exploit it.
D. They were doubtful about its potential economical value.