问题详情

From the text we learn that Welchi ______.
A．is a wicked worm causing as many damages as Blaster did
B．is a program designed by Haley to detect worms like Blaster
C．is a program intended to fix the infected machines
D．is a worm meant to defeat the virus with "pings"请帮忙给出正确答案和分析，谢谢！