Why Are Most Rich Doughs Mixed Using the Sponge Method

Why are most rich doughs mixed using the sponge method?

A) The high percentage of fat and sugar in these doughs inhibits fermentation, and in the sponge method, most of the fermentation has already taken placed before the fat and sugar is added.
B) The sponge method requires more time than other mixing methods, thereby allowing more gluten to form in these doughs than in leaner doughs.
C) The sponge that is formed traps more moisture, which inhibits the fermentation process and allows these doughs to rise higher than lean doughs.
D) All of the above are true.