Grains of Basmati rice get elongated on being cooked because of higher content of:

The answer is B) Amylose. Basmati grains elongate mainly lengthwise when cooked, and this behaviour is linked to their relatively high amylose content. Amylose is the straight-chain component of rice starch. Its structure limits radial swelling and pushes the expansion along the length of the grain, which is why cooked Basmati looks long and slender.

• A) Lysine is an essential amino acid. It matters for protein nutrition, not for grain shape on cooking.
• C) Sugar is not the determinant. Rice contains little free sugar, and it does not explain the elongation.
• D) Oil is present in very small amounts in milled rice. Its relevance is to storage and rancidity, not to texture or shape.

The core concept is the starch composition of rice (amylose versus amylopectin) and its effect on cooking quality. This links to the Mains angle of Basmati's Geographical Indication status and the export-quality parameters that depend on grain length and elongation.

Trap: Aspirants often confuse aroma, which comes from the compound 2-acetyl-1-pyrroline, with elongation. Aroma and elongation are separate traits.