The plumber couldn't remember where he'd left the box ____________ he kept his tools.5/50Mark the letter A, B, C, or D to indicate the correct answer to each of the following questions. The plumber couldn't remember where he'd left the box ____________ he kept his tools.for whomin whatin whichof whichGiải thíchĐáp án C Đại từ quan hệ: in which = where