Deed of rectification has to be executed by A to mention correct survey number in

plot sold to B 

For subsequent sales also deed of rectification has to be executed 

See a rectification suit can be filed before the civil court to correct survey no. In sale deed since the older parties may not be available the court shall pass order on same.

Yes you need to approach court to correct same.

A  legal heirs can execute deed of rectification 

2) it should be duly stamped and registered 

3) if they refuse to execute deed of rectification you may file a suit before a court under Section 26 of Specific Relief Act 1963. The law provides for relief to parties in case the real intention of the party is not properly reflected in the documents executed because of a bona fide mistake of fact.

. The court can direct the rectification of an instrument, if it is satisfied that the deed does not express the real intention of the parties. This relief is entirely discretionary.

excute a rectification deed  if A is live.  If he died then approach A legal heirs and rectify. 

Apply for rectification in sale deed at sub registrar office. And c and d presence only. 

As A is reported to be not alive, it would suffice if C executes a rectification deed clearly bringing out all the relevant facts, including the death of A. It has to be duly stamped and registered.

If the survey number has been wrong in the registered sale deed, then you may have to ask your vendor to execute a registered rectification deed rectifying the mistake or error.

Let your vendor approach his vendor and so on until this error is rectified.

First of all you try to rectify the error through your vendor, later on you can decide about the legal process to rectify the same if it it is stuck anywhere and not progressing.

You need to execute a rectification deed for the same

1.  Apply for "Govt. Survey" (not private survey) with the local Tahsil office, by providing all available documentations.

2.  Based on the Govt. Survey REPORT, you can unilaterally register & execute proper "rectification deed" before the local office of the Registrar of Sub-Assurances.  This would be legally sufficient for all futuristic purposes like Sale /Transfer /Mortgage/ Gift /Donate /whatever....

1. For getting the survey number amended/ corrected, you will have to make an application for the inspection of the property and correct the record of the authority before the Tehsildar or SDM of your district.
2. Once that is been done then with Mr. C go for the rectification deed for the sale deed and get the rout numbest printed in it and get it duly registered before the Registrar’s office.
3. If anything goes wrong then you may have to approach the court of law for the direction to the authorities to do the needful.