Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: Amylose is insoluble in water.
Reason R: Amylose is a long linear molecule with more than 200 glucose units.
In the light of the above statements, choose the correct answer from the options given below.

We need to evaluate the Assertion and Reason about amylose.

Assertion A: "Amylose is insoluble in water." — Amylose is actually soluble in hot water, and it can form a colloidal solution. It is amylopectin (the branched component of starch) that is insoluble in water. Therefore, Assertion A is incorrect.

Reason R: "Amylose is a long linear molecule with more than 200 glucose units." — This statement is correct. Amylose is indeed a linear (unbranched) polymer of glucose units connected by $$\alpha$$-1,4-glycosidic linkages, and a typical amylose chain contains 200 to several thousand glucose units. The linear structure allows it to adopt a helical conformation.

Since Assertion A is not correct (amylose is not insoluble in water) but Reason R is correct (amylose is indeed a long linear chain with more than 200 glucose units), the appropriate choice is that A is not correct but R is correct.

Hence, the correct answer is Option D.