Beth is correct as always,
and
to be specific, the center drive pulley is the one that has a groove that accepts either a 1/2" or 5/8" drive belt from the engine.
Sometimes the pulleys are stuck on the shaft, so use P&P ( patience and perseverance) when using penetrating oil
Pullers are to be used with great caution as many times one gets overzealous and ruins the pulley edge.
The pulleys are not cheap and IIRR, it has been mentioned they were NLA but not sure on that.