How did the the Khmer civilization shape culture in Southeast Asia? Select the two correct answers. 30 POINTS PLS HELPPPPP QUICK

A.
innovated a feudal system based on the loyalty of samurai warriors

B.
developed writing systems that spread throughout Asia

C.
used irrigation canals and reservoirs to support large-scale rice farming

D.
introduced Islam via Indian Ocean trade routes

E.
built vast Buddhist temple complexes