Once the cause in fact is established, the plaintiff must establish , that is the harm by the injured person that was a foreseeable consequence of the defendant’s negligent actions.

they encountered severe weather for which they were poorly prepared.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."