Which of the following statements about Voice over Internet Protocol (VoIP) is correct?

Introduction / Context:
Voice over Internet Protocol, usually shortened to VoIP, is a technology that allows voice communication over IP networks such as the internet. Many popular applications and services use VoIP to provide audio and video calls between users. This question asks you to identify a correct statement about VoIP from a set of options that intentionally mix correct and incorrect ideas.

Given Data / Assumptions:

• VoIP carries voice traffic using Internet Protocol packets.
• Popular applications like Skype use VoIP behind the scenes.
• Traditional public switched telephone network and dial up connections are different technologies.

Concept / Approach:
VoIP works by converting voice signals into digital data and then sending that data as IP packets across networks. On the receiving side, the packets are reassembled and converted back into audio signals. While some VoIP systems may interconnect with the traditional public switched telephone network at gateways, the core idea is that the voice calls travel over IP networks rather than solely over circuit switched telephone lines. VoIP is well suited to broadband connections that provide higher bandwidth and better quality. Applications such as Skype, Zoom, and many messaging apps are clear examples of VoIP in action.

Step-by-Step Solution:
Step 1: Evaluate option A. Saying that VoIP always uses the traditional public switched telephone network directly ignores the fact that VoIP calls often travel entirely over IP networks.Step 2: Evaluate option B. Skype indeed uses VoIP technology to carry voice and video over the internet.Step 3: Evaluate option C. VoIP can work over various types of internet connections, and broadband is preferred for quality. It is not limited to dial up.Step 4: Since only option B correctly describes VoIP, option D, which claims all statements are correct, must be false.

Verification / Alternative check:
Think about how you use Skype or similar applications. You connect to the internet and can call another user anywhere in the world without using a traditional telephone line directly. The application uses your internet connection to send voice data as packets. In some cases, you can call normal phone numbers through a gateway, but the core technology is still Voice over IP. This confirms that the statement naming Skype as an example of VoIP software is accurate.

Why Other Options Are Wrong:
Option A: Misleads by referring only to the public switched telephone network, which VoIP may connect to but does not always use directly.Option C: Suggests that VoIP requires slow dial up connections, which is the opposite of reality; higher speed broadband is much more suitable.Option D: Cannot be correct because it includes options A and C, which are not accurate.

Common Pitfalls:
One pitfall is assuming that VoIP is just another name for normal telephone service. Another is thinking that VoIP quality must always be poor because it uses the internet. In practice, modern VoIP with good bandwidth can provide very high quality audio and additional features like video calls and instant messaging in one integrated service.

Final Answer:
The correct answer is Skype is an example of VoIP software that carries voice calls over IP networks.