When a document repository is down when you attempt to access it, the ISA principle Authentication is being violated. The authentication method is done during the log on phase and is performed by the ISA server which requests certificate. <span>The client then needs to send the appropriate client certificate to the server in order to be authenticated and to have access to the document.</span>
        
             
        
        
        
Answer:
D. a potential hazard
Explanation:
Abrupt changes in road surface or the shape of the road may indicate a potential hazard.
 
        
                    
             
        
        
        
Answer:
Option (b) When the end-user device will run an application that requires a dedicated connection to the network 
Explanation:
- Option (b) is the correct option. 
- When the user device requires a highly dedicated network environment to itself to run a web application that requires large download and upload speeds, bandwidth requirements then it prefers a wired connection than a wireless connection.
- If the wireless signal is within the reach, then it advisable to go for a wireless connection than a wired connection. A wired connection requires other hardware equipments like a internet connection cable etc. which is not required in case of wireless connection. So, option (a) is wrong option.
- WLAN NIC is a wireless interface network controller that connects to a wireless radio based network than a wired network.So, option (c) is wrong option. 
- Delay torrent network is designed to operate where continuous network connectivity is not available like extreme terrestrial spaces, space communications, inter planetary communications etc.So, option (d) is wrong option.