(Red Mansion) Who Is My Adopted Sister?

Once Liu Qinghu crossed over, he became the only son of Yanhu in the south of the Yangtze River. This salt farmer had a son in his forties, and his family had a permanent income, so he was born in Liuqing Lake and did not suffer much. Until one day, Shiotou was seriously ill and felt that his end was approaching. He pulled Liu Qinghu to the bed, took out nine orchid hairpins, and "Son, dad is dying. He has a last wish. One of these nine orchid hairpins belongs to your adopted sister. You go find her and help dad see if she is dead or alive." Liu Qinghu looked at the nine hairpins and was stunned. Which of these nine hairpins belongs to his adopted sister? Purpose: family reunion