BLACKSBURG - Virginia Tech head wrestling coach Keith Mourlam  announced Tuesday the signing of four athletes who will enroll at Tech and join the wrestling squad for the 2002-03 school year.    Andrew Donofrio chose the Hokies over national powerhouse Oklahoma State. The native of Oxford, Pa., who attends St. Mark's (Del.) High  went 45-3 last year as a junior in winning the Delaware state  hampionship at 145 pounds. He also won the Delaware state title as a freshman at 119 pounds and as a sophomore at 140 pounds. In three years, he is undefeated in dual meets and was a high school All-American a year ago. Heading into his senior season, he has a record of 120-11. He will likely wrestle at 149 or 157 pounds in college.    Kyle Graham boasts a 140-13 career record heading in his senior season at Colonial Forge High in Stafford, Va. He posted a 50-3 record as a junior, winning the state freestyle championship, and a 49-3 mark as a sophomore. The 125-pounder is a two-time member of the Virginia National Freestyle team and won both the Herndon Holiday Classic and Eagle Holiday Classic last year.    Tyde Prater is the third Grundy (Va.) star to sign with the Hokies in the four years. Current standout Scott Justus, and Prater's brother, Canaan, both wrestled in that superb program. Prater, who will likely wrestle at 141 pounds, is a three-time state finalist and has won the Virginia state championship twice. He is also a three-time regional and district champion. Prater also stars on the football team, earning all-district and all-region honors. He is an honor roll student who currently carries a 3.8 GPA.    Chris Stith rounds out the early signing class. The junior college transfer will help the Hokies at either 157 or 165 pounds. A native of Virginia Beach, Va., Stith won a state title for Cox High School in 1999 and finished third at the high school nationals before heading to Neosho (Kan.) Community College. Stith redshirted a year and is currently ranked sixth in the JUCO polls at 157 pounds. Stith, who chose the Hokies over Arizona State, will be a sophomore when he arrives next year.    "I think we filled some big holes," Mourlam said, "especially at the lower and middle weights. This is a great group of wrestlers, both technically and athletically. I look for them to be major contenders  right away."