Let’s break it down with some quick explanations for each option:

- Option 1: `two2`
This one’s fine. It starts with a letter and only has numbers at the end. Python likes that.

- Option 2: `_main`
Also valid. Identifiers can start with an underscore. In fact, underscores are pretty common in Python variable names.

- Option 3: `hello_rsp1`
Totally allowed. Letters, underscores, and numbers (but not as the first character) are all good.

- Option 4: `2 hundred`
Here’s the catch: Identifiers can’t start with a number, and they can’t have spaces. This breaks both of those rules. ❌

So, the correct answer is:
**Option 4 – 2 hundred** ✅

YOUR ANSWER IS RIGHT