` C_6 H_5`-group causes - l-effect when present in a saturated chain of carbon atoms.

Explanation

To solve the question regarding the -I (minus inductive) effect of the C6H5 group (phenyl group) when present in a saturated carbon chain, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding the Phenyl Group**:
The phenyl group (C6H5) is derived from benzene, which has a structure consisting of six carbon atoms arranged in a ring, with alternating double bonds. When we refer to the phenyl group, we are considering it as a substituent attached to another carbon atom.

2. **Hybridization of Carbons**:
...