Which of the following accurately describes a flat yield curve?

A curve that rises sharply and then levels off as maturities lengthen and that indicates a transition between a period of economic stagnation to one of growth.
A curve with a minimal spread between short-term and long-term maturities and that indicates concern or doubt about the strength of the economy.
A curve that slopes downward as maturities lengthen and that indicates confidence that economic activity will grow in the future.
A curve that slopes upward as maturities lengthen and that indicates fear that the economy is about to enter a recession.