请阅读Passage 2，完成小题。
Passage 2
For hundreds of millions of years,turtles have struggled out of the sea to lay their eggs on sandy?beaches,long before there were nature documentaries to celebrate them,or GPS satellites and?marine biologists to track them,or volunteers to hand-carry the hatchlings down to the water′s edge?lest they become disoriented by headlights and crawl towards a motel parking lot instead．A?formidable wall of bureaucracy has been erected to protect their prime nesting on the Atlantic?coastlines．With all that attention paid to them,you′d think these creatures would at least have the?gratitude not to go extinct．
But Nature is indifferent to human notions of fairness,and a report by the Fish and Wildlife?Service showed a worrisome drop in the populations of several species of North Atlantic turtles,notably loggerheads,which can grow to as much as 400 pounds．The South Florida nesting?population,the largest,has declined by 50%in the last decade,according to Elizabeth Griffin,a?marine biologist with the environmental group Oceana．The figures prompted Oceana to petition the?government to upgrade the level of protection for the North Atlantic loggerheads from"threatened"to"endangered"--meaning they are in danger of disappearing without additional help．
Which raises the obvious question:what else do these turtles want from us,anyway?．It turns?out,according to Griffin,that while we have done a good job of protecting the turtles for the weeks?they spend on land(as egg-laying females,as eggs and as hatchlings),we have neglected the years?they spend in the ocean．"The threat is from commercial fishing,"says Griffin．Trawlers(which drag?large nets through the water and along the ocean floor)and longline fishers(which can deploy?thousands of hooks on lines that can stretch for miles)take a heavy toll on turtles．
Of course,like every other environmental issue today,this is playing out against the?background of global warming and human interference with natural ecosystems．The narrow strips?of beach on which the turtles lay their eggs are being squeezed on one side by development and on?the other by the threat of rising sea levels as the oceans warm．Ultimately we must get a handle on?those issues as well,or a creature that outlived the dinosaurs will meet its end at the hands of?humans,leaving our descendants to wonder how creature so ugly could have won so much affection．
What constitutes a major threat to the survival of turtles according to Elizabeth Griffin?
A.Their inadequate food supply
B.Unregulated commercial fishing
C.Their lower reproductive ability
D.Contamination of sea water