They are solids at room temperature. They don't conduct electricity. They are brittle and dull. They are radioactive.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: All elements found on the left side of the Periodic Table of the Elements have what properties in common?
Possibilities:
- They are solids at room temperature.
- They don't conduct electricity.
- They are brittle and dull.
- They are radioactive.

They are solids at room temperature.