Step 1: Concept
Chlorine, Fluorine, and Iodine are chemical elements found in Group 17 of the periodic table.
Step 2: Meaning
The common group name for these elements is "Halogens".
Step 3: Analysis
- They are not inert gases (Group 18).
- Iodine is a solid at room temperature, not a gas.
- They are non-metals, not transition elements.
Step 4: Conclusion
They are all categorized as halogens.
Final Answer: (d)