he is one of the students who-----praised by the teacher.

选A在定语从句的习惯使用中,one of后面的名词是复数,这个复数名词制约后面的定语从句的谓语动词。例如：He is one of the teachers who know French in our school。注意：而在one of 前面有the或 the only时,后面引导的定语从句中的谓语动词则用单数形式。例如：He is the only one of the teachers who knows French in our school。