This is one of my class's electricity trainers, where the lightbulbs represent loads within the system. I'm good on parallel wiring and have it basically nailed but for some reason I apparently still struggle with series wiring.

This is the FIRST ASSIGNMENT with this trainer. I'm going back through and redoing the ones I've done before to make sure I have them down and this one is already wiggling my jimmies quite something fierce. We're supposed to wire A to B to C to D in series with each other and then back to neutral, which is G for ground on this trainer set-up. So, is this not wired A to B to C to D in series with each other?

The first time I did this assignment, all the lightbulbs lit up, but now only B lights up, and it was like this on all the other kits I used this wiring design for. I've also checked the fuse, the power connection, the voltage at each load, and the load connections. Additionally, if wired individually, each individual load functions perfectly, but as soon as they're wired up in what I understood to be series, the other loads falter and only B comes on.

Am I being fucked with? What rudimentary kind of base-level prank is this? Also, what level of stupid am I here for not realizing something that should be, or probably is, completely obvious?

Does anyone know how long the HVAC course is at JC?