He is the only one of the students who

He is the only one of the students who _____ a winner of scholarship for three years.

A.is

B.are

C.have been

D.has been

D

在“one of+复数名词+定语从句”中，定语从句一般被看成修饰复数名词，因此该从句的谓语用复数形式；在“the only one of+复数名词+定语从句”中，定语从句常看成修饰单数名词，从句谓语用单数形式。

This is one of the best novels that have appeared this year.

He was the only one of the boys who was given a prize.

由此可以排除B和C；

“for+时间段”是现在完成时态的时间状语，故选D项。