Usage of which - Question

[sohrabkalra]

The methodology of historical inquiries, which in the past has depended largely on the accesibility of written records, will be greatly affected by the revolution in communications

A)which in the past has depended
B)which in the past have depended
C)which in the past has been dependent
D)that has in the past been dependent
E)that had been depending in the past

OA after discussion

[avik.ch]

From the meaning of the sentence -- "which" refer to "methodology" because its saying that in the past the methodology was dependent on the accessibility of written records. "Historical inquiries" cannot be dependent on the accessibility of written records. Since "methodology" is singular, "has" should be used. Hence B is wrong.

C - "has been dependent" is wrong.

IMO:A

What is the OA ?