Final answer:
Changing -ous to -osity in 'monstrous' alters the word to 'monstrosity,' shifting the meaning from very big to horrible.
Step-by-step explanation:
Changing the suffix in the word monstrous to -osity alters the word significantly. The suffix -osity suggests a state, quality, or condition. Therefore, replacing -ous with -osity in the word monstrous would change the word to monstrosity, which generally means the state or quality of being monstrous, emphasizing the horror or hideousness of something rather than its size. The correct answer is C, that changing -ous to -osity changes the meaning from very big to horrible, as the term monstrosity refers to something shocking or appalling in character or appearance.