Let's say you have a user that adds a sound card and a network card to a PC. Sound card: IRQ=5 ; IO address 300-330 and the NIC's IRQ is 2; IO address is 310-340. Upon boot up the PC complete locks up. Why?

A) The NIC cannot use IRQ2; it is a reserved IRQ
B) A Buggy device driver
C) IRQ conflict between the sound card and NIC.
D) I/O address conflect between the sound card and NIC.

What is the correct answer and why? I'm studying for my A+ certification and rather than memorizing questions, i would prefer to understand the concept behind the answer.

Source: Mike Meyer's A+ Certification Passport 2002 Ed.