16. which process(es) cause(s) thick sediment layers to accumulate along the boundaries of continental
and oceanic plates?
o a. marine transgressions
o b. subduction
o c. marine regressions
o d. glaciation

The process of thick sediment layers to "accumulate" along the "boundaries of continental and oceanic plates" is called Subduction.

Explanation:

During a marine transgression, sea level raises high compared to land level resulting in floods. These are triggered during climate changes, ice-age, isostatic movements. Subduction occurs at the tectonic plates where one plate is moves under another forcing to sink into Earth’s mantle due to the gravitational force. The plates are continental and oceanic in the zone of lithosphere. The rate of subduction is usually seven to 8 centimetres per year. Marine regressions are opposite to transgressions where sea levels fall compared to land levels. Glaciation is the interval of time within an ice-age. The current glacier period is of Holocene.  

D.haka is the first answer and a.canberra is the second answer