The electronic configuration for Neodymium is: [Atomic Number for Neodymium = 60]

🧠 Navigating the f-block Jungle Neodymium lives in the Lanthanoid series (Period 6). For these elements, the filling order follows the $6s \to 4f \to 5d$ route. Key to Z=60 is working forward from the Xenon ($Z=54$) baseline.

🗺️ The Lanthanoid Launch

1. Baseline: Xenon ($Z=54$).
2. Next Steps: $Z = 60 - 54 = 6$ electrons to place.
3. The 6s Buffer: The $6s$ orbital is always filled first with 2 electrons. Remaining $= 4$.
4. Entering the 4f House: For early lanthanoids (like Nd), there is usually $0$ electrons in $5d$. So all $4$ remaining electrons enter the $4f$ subshell. Result: $[\text{Xe}] 4f^4 6s^2$.

⚡ The f-block Offset A useful rule of thumb: For lanthanoids ($Z=57$ to $71$), the number of electrons in the $4f$ subshell is often $(Z - 56)$. For Nd ($Z=60$): $60 - 56 = 4$. So, $4f^4$. (Note: Exceptions like Gd exist, but this works for Nd!)

⚠️ Common Traps Don't jump to option (4) $[\text{Xe}] 4f^1 5d^1 6s^2$. Only Lanthanum ($Z=57$) and Gadolinium ($Z=64$) store a single electron in $5d$ for specific stability reasons. Neodymium follows the standard direct $4f$ filling.

$\boxed{\text{Answer: (a)}}$