Students in Mrs. Nichols' ecology class noted that coastal regions in the state were changing. Areas that had once been only occasionally submerged now remained underwater all year; even low tides did not uncover the once marshy areas. The ecology students hypothesized that the most likely reason for this change in sea level and therefore habitat was
A) global warming.
B) off-shore oil drilling.
C) increased sedimentation.
D) decrease in ocean density.