Which type of sediment is made up mainly of the shells of diatoms and radiolarians?

The type of sediment that is made up mainly of the shells of diatoms and radiolarians are called the siliceous ooze. Siliceous ooze is a siliceous pelagic sediment that covers large areas of the deep ocean floor. Calcareous ooze, siliceous ooze is formed from the tests of microorganisms; in the case of siliceous ooze, the organisms come in two varieties, diatoms and radiolarians.

None   they are   equally likely to occur on any plate boundary

The answer is    d.  central highlands