Trace the historical development of cooking?​

Iwould have made a few comments, and requested a short history of the place from the surly owner; but his attitude at the door appeared to demand my speedy entrance, or complete departure, and i had no desire to aggravate his impatience previous to inspecting the penetralium. what does the term penetralium mean as used in this sentence from the passage? a) inside b) openness c) outside d) privacy