S1 문장의 [______]에 들어갈 단어는?

난이도 고난도 · 힌트를 덜 열수록 높은 점수 (현재 5점)
According to Cambodian legends, lions once roamed the countryside attacking villagers and their precious buffalo, and long before the great Khmer Empire began in the 9th century, farmers developed a [______] martial art to defend themselves against the predator.