In 1929, the great depression began in the united states, caused mainly by the stock market crash. what was a major cause of the stock market crash? a) people were scared by the u. s. involvement in world war i. b) the new york stock exchange was attacked by terrorists. c) stock owners began to panic when stock prices fell. d) people preferred to invest in european stocks.

C

Explanation:

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."