The hybridisation scheme for the central atom includes a d-orbital contribution in:

Options

A. `I_(3)^(-)`
B. `PCl_(3)`
C. `NO_(3)^(-)`
D. `H_(2)Se`

Explanation

To determine which hybridization scheme for the central atom includes a d-orbital contribution, we need to analyze the given options. The key is to identify the steric number and the resulting hybridization of the central atom in each case.

### Step-by-Step Solution:

1. **Identify the Central Atom and Its Valence Electrons:**
- For each compound or ion, identify the central atom and count its valence electrons.

2. **Determine the Bonding Pairs and Lone Pairs:**
- Analyze the structure to determine how many bond pairs (bonds formed with other atoms) and lone pairs (non-bonding electrons) are present around the central atom.

3. **Calculate the Steric Number:**
- The steric number is calculated as the sum of the number of bond pairs and lone pairs.
- Steric Number = (Number of Bond Pairs) + (Number of Lone Pairs)

4. **Determine the Hybridization:**
- Use the steric number to determine the hybridization:
- Steric Number 2: sp
- Steric Number 3: sp²
- Steric Number 4: sp³
- Steric Number 5: sp³d (involves d-orbitals)
- Steric Number 6: sp³d² (involves d-orbitals)

5. **Check for d-Orbital Contribution:**
- If the steric number is 5 or 6, then d-orbitals are involved in the hybridization.

6. **Evaluate the Given Options:**
- Look at each option provided in the question and follow the above steps to see if any of them involve a d-orbital contribution in their hybridization.

### Conclusion:
- The correct answer is the option where the central atom has a steric number of 5 or 6, indicating that d-orbitals are involved in the hybridization.