According to the researchers, what is the average price tag of these fundamental ecosystem services?

According to the researchers, what is the average price tag of these f

1.	According to the researchers, what is the average price tag of these fundamental ecosystem services?
A.	US $ 300 trillion a year
B.	US $ 33 trillion a year
C.	US $ 5 trillion a year
D.	US $ 1000 trillion a year
Answer» D. US $ 1000 trillion a year