This problem is about learning a little more about the DNS and getting rewarded for it. At the bottom of the cloudflare.com web page, there is a link called Learning Center. It is accessible directly through https://www.cloudflare.com/en-gb/learning/. Using this page (or the appropriate RFC if you want to explore more), read the information given there for the DNS system and answer the following questions in your own words (not by copy/paste). 

a) In addition to A, NS, CNAME, and MX resource records, DNS includes many other types of records. Explain what the AAAA and the PTR resource records are used for and how they work. 

b) Explain what DNS poisoning is and describe a method to tackle this problem.