In covalent bond

Options

A. transfer of electrons takes place
B. sharing of electrons takes place
C. electrons are shared by only one atom
D. none of these

Answer

### Step-by-Step Solution:

1. **Understanding Covalent Bonds**:
- A covalent bond is formed when two atoms share one or more pairs of electrons. This sharing allows each atom to attain a stable electron configuration, typically resembling that of the nearest noble gas.

2. **Analyzing the Options**:
- **Option A**: "Transfer of electron takes place" - This describes an ionic bond, not a covalent bond.
- **Option B**: "Sharing of electron takes place" - This is the correct definition of a covalent bond.
- **Option C**: "Electrons are shared by only one atom" - This is incorrect because in a covalent bond, electrons are shared between two atoms.
- **Option D**: "None of these" - This is incorrect since option B is correct.

3. **Conclusion**:
- The correct answer is **Option B**: "Sharing of electron takes place".