Which of the following sets of orbitals are degenerate and why ?
(i) `1s, 2s and 3s` in Mg atom
(ii) `2p_x, 2p_y and 2p_z` in C atom
(iii) `3s, 3p_x and 3d` orbitals in H atom.

Explanation

To determine which sets of orbitals are degenerate, we need to understand the concept of degeneracy in atomic orbitals. Degenerate orbitals are those that have the same energy level. We can use the N + L rule to analyze the energy levels of the orbitals in question.

### Step-by-Step Solution

1. **Understanding Degeneracy**:
- Degenerate orbitals have the same energy. We will analyze the given sets of orbitals to see if they share the same energy.

2. **Analyzing the First Set: `1s, 2s, and 3s` in Mg atom**:
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