I feel like this slide listing two possible answers is slightly misleading. In "possible answer one", it seems we assume that every packet of B bits of data takes T clocks to travel to the destination. That means we really only have an effective, long time average bandwidth of (B/T) bits per clock. If we really had B bits/clk bandwidth, then answer two is the correct one.

I understand bandwidth as a long-time average concept. Is my assumption incorrect?

Nevermind, I looked it up, and bandwidth is a theoretical maximum for transport rate, and throughput is the long time average transport rate I was thinking about!

In CS144 Intro to Network, T0 is called propagation delay, and the N/B is called the packetization delay. These are similar ideas.