Concept:
Fish is processed into various "market forms" or cuts depending on how the muscle is separated from the skeletal structure.
• Whole/Round: Fish as it comes from the water.
• Dressed: Scaled and eviscerated, usually with head and fins removed.
• Steaks: Cross-section slices cut perpendicular to the backbone.
Step 1: Defining the Fillet cut.
A fillet is a fleshy side of the fish cut away from the backbone.
The cut is made longitudinally (lengthwise) along the side of the fish.
Step 2: Structural characteristics.
Because the slice is made parallel to the spine, the resulting piece is largely boneless.
This is the most popular cut for high-end culinary preparations.
Step 3: Comparing with Steaks.
While steaks are cut across the backbone, fillets are sliced away from it.
Therefore, the lengthwise slice from a dressed fish is a Fillet.
Final Answer: (A)