Explanation:

- Bizarre: This word describes something very unusual or strange, often so much that it fascinates or confuses people.

- Option 1, Strange: This word means something odd or unusual, similar to bizarre. Not an antonym.

- Option 2, Usual: This means something that is normal or common and expected. It’s the opposite of bizarre.

- Option 3, Happy: This term refers to a state of joy or pleasure. It’s not directly opposite to bizarre.

- Option 4, Weird: Similar to strange and bizarre, indicating something odd or uncanny. Not an antonym.

The correct antonym is:

Option 2: Usual