Step 1: Wheat dough shows a sticky, elastic and stretchy quality, so Assertion (A) is correct.
Step 2: This quality comes from gluten, a protein formed from gliadin and glutenin present in wheat, which is correctly stated in Reason (R).
Step 3: Since gluten formation is exactly what gives wheat dough its binding and elastic texture, (R) correctly explains (A). The answer is option 1.