Which assignment of 16 C-Class IP Addresses is better for the classless routing?

Question

I've got a task for the classless routing that I really struggle to understand. It goes like this:

Imagine that an institution needs to be assigned 16 class C IP network addresses.

You can either assign a block of Class C addresses from 194.58.80.0 to 194.58.95.0 or the block of addresses 194.58.72.0 to 194.58.87.0.

Which block assignment is better? To answer this question, consider this part of the internet:

Router 1 --> Router 2 --> All 16 C-Class Networks

List the entries in the routing table of R1 for both address blocks, whereby you should manage with as few entries as possible according to the principle of classless forwarding. To answer the question, you are allowed to invent missing IP addresses of R1 and R2. So which assignment is better?

So I'm really got confused how the routing table should work in such cases. I suspect the answer to the question has something to do with the "longest prefix first" rule and the supernet/subnet mask, but putting it all together turned out a real struggle to me.