Network managers have long awaited practical voice-over-IP (VOIP)solutions. VOIP promises (71) network management and decreases costs by (72) a company’s telephony and data infrastructures into one network. And a VOIP solution implemented at a company’ s head -quarters with far -reaching branch offices can (73) tremendous amounts of (74) in long distance phone bills, provided that solution delivers POTS -like voice (75) over the Internet.
（75）处填（）。
A．qualtity
B．quality
C．volune
D．speed
