PLEASE I NEED HELP $AS$ SOON $AS$ POSSIBLE

$1.$ Suppose within your Web browser you click on a link to obtain a Web page. The IP address for the associated URL is not cached in your local host, so a DNS lookup is necessary to obtain the IP address. Suppose that n DNS servers are visited before your host receives the IP address from DNS; the successive visits incur a RTT $($round$-$trip time$)$ of RTT$1,...,$ and RTTn$.$ Further suppose that the Web page associated with the link contains exactly one object, consisting of a small amount of HTML text. Let RTT$0$ denote the RTT between the local host and the server containing the object. Assuming zero transmission time of the object, how much time elapses from when the client clicks on the link until the client receives the object?

$2.$ Referring to Problem $1,$ now suppose the HTML file references seven very small objects on the same server. Neglecting transmission times, how much time elapses with

a$.$ Non$-$persistent HTTP with no parallel TCP connections?

b$.$ Non$-$persistent HTTP with the browser configured for three parallel connections? c$.$ Persistent HTTP$?$