Step 1: Understanding the Concept:
Sorghum (*Sorghum bicolor*) is a major cereal grain.
The endosperm of sorghum is structurally heterogeneous, consisting of different layers with distinct starch packing densities and protein matrix compositions.
Step 2: Detailed Explanation:
The endosperm of a sorghum grain is divided into three distinct zones:
1. Peripheral endosperm: A dense, thin outer layer rich in protein and small starch granules.
2. Corneous (vitreous/steely) endosperm: A hard, translucent outer layer where starch granules are tightly packed in a dense protein matrix.
3. Floury endosperm: A soft, opaque, chalky region located in the central core of the grain. Here, the starch granules are large, loosely packed, and contain air pockets due to a thin, discontinuous protein matrix.
Step 3: Final Answer:
The floury endosperm is present in the central core, which corresponds to option (B).