To solve this problem, we need to understand what substances are translocated by the xylem in plants.$\newline \bullet$Xylem is a type of vascular tissue in plants primarily responsible for the transport of water.$\newline \bullet$However, xylem also transports mineral salts absorbed from the soil.$\newline \bullet$In addition to water and mineral salts, xylem can transport some organic nitrogen compounds.$\newline \bullet$Furthermore, xylem is involved in the transport of plant hormones, which are crucial for growth and development.$\newline$Therefore, xylem translocates water, mineral salts, some organic nitrogen, and hormones.$\newline$This corresponds to Option 4.