Answer: Option C
Answer: (c)
A geosyncline may be defined as “a thick, rapidly accumulating body of sediment formed within a long, narrow, subsiding belt of the sea which is usually parallel to a plate margin”. (Oxford Dictionary of Geography).
Or we may say a geosyncline is a “very large linear depression or down-warping of the earth’s crust, filled (especially in the central zone) with a deep layer of sediments derived from the landmasses on each side and deposited on the floor of the depression at approximately the same rate as it slowly, continuously subsided during a long period of geological time”.