Refund for excess TDS deposited under 26QC

I have submitted my request for refunding excess TDS deposited under form 26QC on traces portal. I have downloaded the acknowledgement form 26B. I understand that the acknowledgement form 26B needs to sent to Assessing Officer. In my refund status tracker, I can see AO address which is in Mumbai as below:

TDS CIRCLE, THANE QUERESHI MANSION,GOKHALE ROAD,NAUPADA, THANE (WEST),NEAR TEEN HATH NAKA,THANE,Maharashtra-400602

I just want to know if it is sufficient to sign the Form 26B acknowledgement and send it to above address by speed post? 

Also, I don't see any email where I can send pdf copy of signed Form26B. 

What shall I do to complete and send the Form26B to AO to get refund. Pls advise.