Final answer:
The number sentence that represents the model 111 is 100 + 10 + 1 = 111.
Step-by-step explanation:
The correct number sentence that represents the model 111 is option A) 100 + 10 + 1 = 111.
The model is broken down into its place values, where the digit 1 represents 1 hundred, the digit 1 represents 1 ten, and the digit 1 represents 1 unit. Adding these three place values gives us the total value of 111.