Final answer:
The correct answer is C) four thirds.
Step-by-step explanation:
In this question, there are six fraction models, each partitioned into three equal parts, with two parts shaded in each model. The answer choices are: A) eight thirds, B) eight ninths, C) four thirds, and D) twelve thirds.
To determine the correct answer, we need to find the total shaded area in all six models. Since each model has two shaded parts and there are six models, the total shaded area is 2 x 6 = 12 shaded parts.
Since each part represents one-third, the total shaded area is 12 x 1/3 = 4.
Therefore, the correct answer is C) four thirds.