Step 1: AFC Formula.
\[AFC = \frac{TFC}{Q}\] where \(TFC\) = Total Fixed Cost, \(Q\) = Output. Step 2: Description.
As output (\(Q\)) rises, Average Fixed Cost (AFC) continuously declines because Total Fixed Cost (TFC) remains constant. AFC approaches zero but never reaches it. The AFC curve is a rectangular hyperbola relative to the axes.
Step 3: Option Evaluation.
- (A) Constant → Incorrect; AFC falls.
- (B) U-shaped → Characteristic of Average Cost (AC) and Average Variable Cost (AVC), not AFC.
- (C) Correct → Matches the rectangular hyperbola shape.
- (D) Reverse hyperbola → Not a recognized term for cost curves.
Conclusion: \[\boxed{\text{Rectangular Hyperbola}}\]