_________, the process by which the State took over from the Church the registration of births, death, and marriages was complete by 1792 in Europe.

The sentence describes a historical process completed by 1792, suggesting a temporal/sequential discourse marker. 'Later' fits as it implies that subsequent to some earlier reference point, the State's takeover of civil registration was completed by 1792 in Europe. 'Besides' (in addition), 'However' (contrast), and 'Instead' (alternative) do not provide the appropriate temporal framing required by the context describing the completion of a historical process. Therefore the answer is (c) Later.