विधान (A): राज्यघटना हा देशाचा सर्वोच्च कायदा आहे.
कारण (R) : जर घटना दुरुस्तीची प्रक्रिया ताठर असेल तरच राज्य घटनेने केलेले सत्ता विभाजन आणि राज्यघटनेचे सर्वश्रेष्ठत्व राखले जाईल.

The correct answer is Option A (Both (A) and (R) are true and (R) is the correct explanation of (A)).

Key Points:
• Supremacy of the Constitution in Federal Systems:
• Assertion (A) is correct: The Constitution is the *grundnorm* or the supreme organic law of India from which all organs (legislature, executive, and judiciary) derive their powers.
• Reason (R) is correct: In constitutional jurisprudence (as noted by A.V. Dicey and K.C. Wheare), a federal system demands constitutional supremacy and division of powers between the Centre and States. If the Constitution could be amended easily by the central legislature at will (a flexible process), the Centre could unilaterally abolish the division of powers, destroying constitutional supremacy. Thus, rigidity in the amendment process regarding federal features is vital to preserve constitutional supremacy.
• Hence, (R) correctly explains (A).
• Key Takeaway: Constitutional supremacy and federal division of powers are safeguarded by a rigid amendment process.