Explanation:

- Francium is the element with atomic number 87. It is a highly radioactive metal in the alkali group, and it's extremely rare in nature.

- Correct Answer: Option 1 - Francium

- Caesium, with atomic number 55, is also an alkali metal. It's known for its use in atomic clocks.

- Lithium has the atomic number 3. It's the lightest metal, commonly used in batteries.

- Rubidium, possessing atomic number 37, is another alkali metal, sometimes used in research and industrial applications.

Based on this information, your answer is right.