What are four chambers of a ruminants stomach?

That all depends on the individual animal you're referring to. Ruminants like cattle, sheep, goats, deer, giraffes, antelope, bison, buffalo, moose, etc. all have four chambers in their stomachs. Camelids like camels, alpacas and llamas only have three compartments. Other animals that are not cud-chewing animals only have one chamber in that one stomach. Such animals are referred to as monogastrics (all apes and monkeys [including humans], pigs, bears, all wild and domestic dogs, all wild and domestic cats, all insects, monotremes, marsupials, etc.), or hind-gut fermentors (all equids like horses, zebras and donkeys, hippos, rhinos, elephants).