Which of the following is erythro from and optically inactive

Options

A.
B.
C.
D.

Answer

To determine which of the given options is the erythro form and is also optically inactive, we can follow these steps:

### Step 1: Understand the Erythro Form
The erythro form refers to a specific type of stereoisomerism where two identical substituents are on the same side of a bond, typically in a molecule with two stereocenters. This form is usually associated with compounds that have a plane of symmetry.

**Hint:** Look for a molecule with two stereocenters where the identical groups are on the same side.

### Step 2: Identify Optical Activity
Optical activity refers to the ability of a compound to rotate plane-polarized light. A compound is optically inactive if it has a plane of symmetry, meaning that the two halves of the molecule are mirror images of each other.

**Hint:** Check for the presence of a plane of symmetry in the molecular structure.

### Step 3: Analyze Each Option
- **Option A:** Check for symmetry. If the groups are not arranged symmetrically, it is likely optically active.
- **Option B:** Similar analysis as Option A. If the groups are not symmetrically arranged, it is likely optically active.
- **Option C:** Look for symmetry. If you find that there are identical groups on the same side and a plane of symmetry exists, this option may be optically inactive.
- **Option D:** Again, check for symmetry. If there are identical groups on opposite sides, it may not be optically inactive.

### Step 4: Conclusion
After analyzing the options, we find that:
- **Option C** has a plane of symmetry due to the arrangement of the groups, making it optically inactive and the erythro form.

**Final Answer:** The correct answer is **Option C**.