Concept:
Basmati rice is a premium quality aromatic rice. It is mainly identified by its special fragrance, long slender grains, and excellent elongation after cooking.
Step 1: Understand the important quality features of Basmati rice.
The important features of Basmati rice include:
\[
\text{Aroma}
\]
\[
\text{Long slender grain}
\]
\[
\text{High grain elongation after cooking}
\]
\[
\text{Good cooking quality}
\]
Step 2: Check option (A).
Aroma is one of the most important features of Basmati rice. Basmati rice is famous for its characteristic fragrance.
\[
(A) \text{ is a key feature}
\]
Step 3: Check option (B).
Grain elongation ratio is also an important feature. Basmati rice grains elongate significantly after cooking.
\[
(B) \text{ is a key feature}
\]
Step 4: Check option (C).
Grain length after cooking is also important because Basmati rice becomes long and fluffy after cooking.
\[
(C) \text{ is a key feature}
\]
Step 5: Check option (D).
High amylose content is not considered a special identifying key feature of Basmati rice in comparison to aroma and grain elongation.
\[
(D) \text{ is not a key feature}
\]
\[
\therefore \text{Correct Answer is (D)}
\]