The first choice is correct
The answer is Monotonous.
eg. Talking in a monotonous voice.
Answer:
1. "Nina rose her hand and said I have too many wrong."
2. "Yes, I have written a letter to Julies' parents."
3. "The twentieth century has brought forth many exciting discoveries."
4. "Have you read Devil Diver, Mr. Blakes' exciting short story?"
Explanation:
Hope this helps! ^^