Which equation is represented by the graph below? On a coordinate plane, a curve approaches y = 0 in quadrant 2 and then increases exponentially in quadrant 1. It crosses the x-axis at (0, 0.5).
y = one-eighth e Superscript x
y = one-half e Superscript x
y = 2 e Superscript x
y = 8 e Superscript x