A collision domain is a segment of network that more than one station can can transmit on the same media at one time. This does not include a full duplex connection, since the physical media is actually 2 sets of wires in the CAT 5/6 cable. Commonly a collision domain would be stations connected to a coax (Thinnet/Thicknet) cable, or hubs. In newer switch based networks, each station is in it’s own collision domain.

RIP and RIPv2 count router hops, while (simplifying things a lot) EIGRP and OSPF use formulas to calculate the cost of links, so a slower like has a higher cost than a faster link. Static routes do not calculate a cost.

This question takes 2 factors into account, the longest match and the Administrative distance. The answers routes are evaluated as follows:

EIGRP route to 172.16.1.0/25 – Not a valid route to 172.16.1.200, it only includes 172.16.1.0 – 127.

Static route to 172.16.1.0/23 – Normally a static route is preferred over dynamic routes, but the /24 routes are a closer match, and the closest match wins.

RIPv2 and OSPF routes to 172.16.1.0/24 – Since these are the same length match, the decision comes down to the Administrative Distance of the routes, and Cisco routers will prefer the OSPF route.

The addresses are invalid for the following reasons:

2001:db8::506a:3b10::1 – Two sets of double Semicolons. Only one set is allowed, since there is no way to know how many 0s go into each one.

2001:db8:1000:50:301:4:2:91:df – Too long, 9 sets of characters

2001:db8:506h:3b10::1 – “h” is not a valid hex digit

See more here: Practical OSI Layers – Part 1