The old man is working in this factory. I borrowed his bicycle yesterday

The old man is working in this factory. I borrowed his bicycle yesterday.
A.The old man is working in this factory which I borrowed his bicycle yesterday.
B.The old man whose bicycle I borrowed yesterday is working in this factory.
C.The old man whom is working in this factory I borrowed his bicycle yesterday.
D.The old man whom I borrowed his bicycle yesterday is working in this factory.
Cho mình hỏi tại sao câu D lại ko chọn được? câu B đúng nhưng câu D có gì sai ko ạ?