खालीलपैकी कोणते विधान योग्य नाही ?

The correct answer is Option C (The 700 km thick layer between the outer core and the inner core is called Transition zone.).

Key Points:
• Earth's Internal Seismic Discontinuities:
• Statement 1 (Correct): Conrad discontinuity separates the Upper Crust (Sial) and Lower Crust (Sima).
• Statement 2 (Correct): Mohorovičić (Moho) discontinuity separates the Crust/Lithosphere from the Mantle.
• Statement 3 (Incorrect): The boundary between the Outer Core and Inner Core is called the Lehmann Discontinuity (at ~5,150 km depth). The Transition Zone of the mantle lies in the upper mantle between depths of 410 km and 660 km (Repetti discontinuity), NOT a 700 km thick layer between outer and inner cores.
• Statement 4 (Correct): Gutenberg discontinuity separates the Lower Mantle from the Outer Core at a depth of ~2,900 km.
• Thus, Statement 3 is incorrect (Option 3).
• Key Takeaway: Moho separates crust-mantle, Gutenberg separates mantle-core, Lehmann separates outer-inner core; statement 3 is incorrect.