Which of the following statements is correct in the context of proof of execution of a document…

It is sufficient to prove the signature of the executor of the document as being in his own handwriting.

It is sufficient to prove that the signature of both the attesting witnesses is in their own handwriting.

It must be proved that the attestation of at least one attesting witness is in his handwriting and that the signature of the executor of the document is in the handwriting of that person.

It is sufficient to prove that the attestation of one attesting witness at least is in his own handwriting.