Which of these gyms will take the longest to beat?

I understand that no gym will deter a determined attacker with time on hand. Just trying to see what would make it most painful/take longest/deplete most resources.

A. Chansey (ZH-DG) > Slowbro/Slowking (C-IB/B) > Vaporeon (WG-AT) > Umbreon (S-FP) > Steelix (IT-HS) > Blissey (ZH-DG)
B. Snorlax (ZH-BS) > Exeggutor (C-SoB) > Lapras (IS-B/IB) > Slowbro/Slowking (C-IB/B) > Steelix (IT-HS) > Blissey (ZH-DG)
C. Vaporeon (WG-AT) > Wobbuffet (C-MC) > Blissey (ZH-DG) > Wigglytuff (FA-PR/DG) > Snorlax (ZH-BS) > Chansey (ZH-DG)

Assume the Pokemon are at high-level and these gyms are fully motivated.

Feel free to suggest your own set of defenders (specifying order of placement).