An isotone of `._(32)^(76)Ge` is-
(a) `._(32)^(77)Ge`
(b)`._(33)^(77)As`
(c)`._(34)^(77)Se`
(d)`._(34)^(78)Se`

Answer

To find an isotone of the isotope \( _{32}^{76}Ge \) (Germanium-76), we need to understand the definition of isotones. Isotones are atoms that have the same number of neutrons but different numbers of protons (atomic numbers).

### Step-by-Step Solution:

1. **Identify the number of neutrons in Germanium-76**:
- The number of neutrons can be calculated using the formula:
\[ \text{Number of neutrons} = \text{Mass number} - \text{Atomic number} \]
- For Germanium-76:
\[ \text{Number of neutrons} = 76 - 32 = 44 \]

2. **Check each option to find the one with the same number of neutrons (44)**:
- **Option (a)**: \( _{32}^{77}Ge \)
- Neutrons = \( 77 - 32 = 45 \) (not isotone)
- **Option (b)**: \( _{33}^{77}As \)
- Neutrons = \( 77 - 33 = 44 \) (isotone)
- **Option (c)**: \( _{34}^{77}Se \)
- Neutrons = \( 77 - 34 = 43 \) (not isotone)
- **Option (d)**: \( _{34}^{78}Se \)
- Neutrons = \( 78 - 34 = 44 \) (isotone)

3. **Conclusion**:
- The isotones of \( _{32}^{76}Ge \) are:
- \( _{33}^{77}As \) (Option b)
- \( _{34}^{78}Se \) (Option d)

### Final Answer:
The isotones of \( _{32}^{76}Ge \) are **(b) \( _{33}^{77}As \)** and **(d) \( _{34}^{78}Se \)**.