Please help me, thanks

Read the following passage : sari was worried. tommorow she was going to take an sat. even though she had prepared, she was still nervous. what if she didn't do well? her future depended on how well she did. she made sure to get a good nights sleep and eat a healthy breakfast. after completeing the test, she realized she worried over nothing. the test was a peice of cake; she was positive she did well. what role does the idiom in this passage serve? a.)it shows that sari didnt prepare b.) it shows that sari was worried over the test at first. c.) it shows that sari was concerned about her future. d.) it show that sari thought the test was easy