The ornamental design for a C-shape fly, as shown and described.
1. C-shape fly applied to Trousers
2. C-shape fly applied to Jeans
1.0: front
2.0: front
The designs consist of a C-shape fly applied to front portions of bifurcated garments as shown in solid lines. The broken lines represent portions of the C-shape fly which form no part of the claimed design. Views not show in the figures form no part of the claimed design.