The graph below shows the temperature of ocean water at different depths.
Graph shows temperature of ocean on x axis and depth of ocean on y axis. The points A(27, 0), B(24, 100), C(11, 200), (9, 300), (8, 400), D(7, 500), (6, 600), and E(5, 800) are joined with straight lines.
Which part of the graph represents the thermocline? (4 points)
a
AB
b
BC
c
CD
d
DE