The Narmada River is one of the major rivers in central India. It flows through four states - Madhya Pradesh, Gujarat, Rajasthan, and Maharashtra. The question asks which state does not form part of the Narmada basin.

Option 1: Madhya Pradesh - This state does form part of the Narmada basin. The Narmada river originates in Madhya Pradesh near the Amarkantak plateau.

Option 2: Gujarat - This state also forms part of the Narmada basin. The river flows through Gujarat before emptying into the Arabian Sea.

Option 3: Rajasthan - This is the correct answer. Rajasthan does not form part of the Narmada basin. The Narmada river does not flow through Rajasthan.

Option 4: Maharashtra - This state too forms part of the Narmada basin. The river flows through Maharashtra before entering Gujarat.

Therefore, option 3, Rajasthan, is the correct answer as it is the only state listed that does not form part of the Narmada basin.