In Oswald Spengler's Cyclical Theory of History, which of the following statements are CORRECT?

(a) Each culture goes through distinct stages of growth, maturity, decline, and eventual death.
(b) Spengler believed Western Civilization had already reached its peak and was entering a period of decline.
(c) Unlike some cyclical theories, Spengler did not posit the possibility of rebirth or renewal for cultures.
(d) Spengler's theory emphasized the role of technology and economic factors as the driving forces of historical change.