The $ sign denotes a row or a column as absolute. Since the rows are numbers (columns are letters), you're looking for an answer with a $ sign in front of a number.
That's answer D I would say.
Your browser references a DNS server that translates a word or phrase of a url into an IP and then tells your browser what the IP address is so the browser can navigate to it. My google is not working atm sorry but you can google "what does DNS stand forin networking" and get an answer.
Answer:
Some constraint are automatically applied by the software while others must be entered manually because we have some shapes that just come with automatic constraint.
In instance can be given with square, this have all ot iits four sides equal with two set of parallel sides.
Explanation:
see Answer.
The obvious answer is
Layer 3, the network layer. but it's not always the case.
Point in case. Since firewalls essentially filter data, the answer depends on what kind of filtering you do.
If you filter based on IP address (for example), you can say that your firewall is filtering at layer 3. If you filter specific ports, you can say you're filtering at layer 4. If your firewall inspects specific protocol states or data, you can say it operates at layer 7.
The truth is that most firewalls do all these things in combination. So practically speaking there really is no useful answer to your question.