Many of the islands of indonesia (java, sumatra, borneo), which are located adjacent to a subduction zone next to the edge of the continental shelf of se asia, consist of felsiclava. this means that the lava that produces these islands is derived from

a) a midocean ridge.

b) a volcanic hot spot under the ocean floor.

c) the melting of continental shelf material along with ocean floor material.

d) the melting of subducted plate material and nothing else.

e) a rift zone