Explanation:

- In the sentence, "It is difficult for us to imagine how much this safety means to everyone," the word "imagine" is about forming a mental picture or concept.

- Option 1: feel - refers to experiencing emotions or physical sensations, not directly linked to forming mental images.

- Option 2: understand - means to comprehend or grasp ideas, which is related but not as close as "think."

- Option 3: think - involves mental activity, including contemplation, making it closely related to the act of imagining. Correct Answer

- Option 4: see - usually refers to visual perception but can imply understanding or conceptualizing, which relates to "imagine."