Melocactus azureus Cactus Care is more similar to

Care is more similar to a succulent too

They are probably E

When actively growing the plant has thin leaves

In late summer/early fall they flower

Melocactus azureus Cactus Care is more similar toMelocactus azureus Family: Cactaceae. This is a nice cephallium forming cactus with blue to blue green skin. It looks and grows like a normal cactus for several years but once it gets big enough the main plant stops growing but produces a large hairy inflorescence that continues to grow for the rest of the life of the plant. Eventually the inflorescence can be taller than the plant itself. This is more tropical than most cacti so it doesn't like cold