Which of the following is the strongest `-I` group?

Options

A. `-overset(+)(N)(CH_(3))_(3)`
B. `-overset(+)(N)H_(3)`
C. `-overset(+)(S)(CH_(3))_(2)`
D. `-F`

Explanation

To determine which of the following is the strongest -I (minus inductive) group, we need to analyze the inductive effects of various substituents. The -I effect refers to the electron-withdrawing ability of a group through sigma bonds due to electronegativity differences.

### Step-by-Step Solution:

1. **Identify the Groups**: First, we need to identify the groups we are comparing. Common -I groups include nitro (-NO2), cyano (-CN), halogens (like -F, -Cl, -Br), and others like -N(CH3)3.

2. **Understand the Inductive Effect**: The -I effect is influenced by the electronegativity of the atoms in the group. The more electronegative the atom, the stronger the -I effect it exerts.

3. **Order of -I Groups**: The typical order of -I groups from strongest to weakest is:
- -N(CH3)3 (trimethylammonium)
- -NO2 (nitro)
- -CN (cyano)
- Halogens (-F, -Cl, -Br, -I)
- -OH (hydroxyl) can also be considered but is generally not classified as a -I group.

4. **Analyze the Given Groups**: In the context of the question, we are comparing the groups mentioned in the video transcript. The strongest -I group is the one that can withdraw electrons most effectively.

5. **Conclusion**: Based on the analysis, the strongest -I group among the options given is -N(CH3)3 (trimethylammonium). This is because it has a positive charge on nitrogen, which enhances its ability to withdraw electrons through the inductive effect.

### Final Answer:
The strongest -I group is **-N(CH3)3**.