A 19-year-old woman pleaded no contest to misdemeanor manslaughter charges stemming from an accident last October that killed four bicyclists. Catherine Ann Miller entered the plea before Gilroy Municipal Judge Alfonso Fernandez who set sentencing for April 27. Each count carries a maximum penalty of one year in jail and a $1,000 fine. The plea means Miller will offer no defense, although she is not admitting guilt. Her attorney, Jesse Ruiz, noted that his client has been in therapy since the accident. "She's been traumatized by the whole thing," he said. "She's carrying around a lot of guilt." Described by authorities as the worst bicycling accident in state history, the accident killed Lawrence Mallery, 54, and his wife, Donna, 46, of Morgan Hill; and Victor Amerio, 53, and his wife, Darlene, 53, of Los Altos. The four were riding single file when they were struck from behind by Miller's car. She told the California Highway Patrol she had taken her eyes off the road to reach for a cassette tape.