TOEIC・English Undergraduate almost 6 yearsago

問2です なぜ④となるのか教えてください

⑧ to hear @ to hear that 了アmn PBBABB も 賠1 ① for hearing ② with heard 癌2 She [sz 1o know that her father got home safely from the mountain8. ① torelieve ② wa relieving ⑧ reheves @ as reheved 閣3 He 5史 such good classmate8. @② is lucky to have ir haas