Exam application form-signature requirement

Hi,

 I am appearing for the May, 2015 IPCC exam after a long gap of 4 years. I was previously registered for the old PCC course, later I converted to IPCC.

 I have already completed my 3.5 years of articleship way back in May, 2011.

 Now, my question here is that is it necessary to procure/take signature of the principal from where I completed my articleship or signature of any member of ICAI will be enough on the exam application form?

 Kindly reply asap.

Regards,

Siddharth