The Problematic Promissory Note

Charge: income tax evasion for the year 1991. Using the net worth method the government seeks to prove that D substantially understated his income in 1991 and owed approximately $13,000 more in taxes than he paid. In defense, D offers in evidence a 1990 promissory note signed by his brother, B, to prove that part of the unreported income the government claims he received was actually a nontaxable loan repayment. What foundational proof will suffice to admit the note:

(1) Testimony of a witness that he was familiar with B's handwriting and that the signature on the note appeared to be B's?

(2) Testimony of a witness that he had represented B for several years, had seen him sign hundreds of documents, was able to recognize B's handwriting, and identified the signature on the note as B's?

(3) Testimony of D that he had seen B sign the note?

(4) Testimony of a witness that, in preparation for the trial, he had examined several exemplars of B's signature, conceded to be valid, and that in his opinion the note was signed by B?

(5) An offer by D's attorney to submit the note and the concededly valid exemplars to the jury for its comparison?

Suppose the authenticity of the exemplars of B's signature was challenged. Who resolves the issue of their admissibility and on what basis? If none of the above testimony is offered, may the note nonetheless be admitted? Before the note is admissible, must D offer testimony by the maker, the payee, or someone who prepared the note to testify as to the transaction of which it was a part?