Signature and verification.

(a) A return shall not be valid unless it is signed. Husband and wife both shall sign a joint return.

(b) Any person, firm, or corporation who prepares the return of a taxpayer shall sign. If the return is prepared by a firm or corporation, the return should be signed in the name of the firm or corporation.

(c) The signature on the return verifies by written declaration under penalties of perjury that the individual has personally examined the return and to the best of his knowledge, the return is true, correct, and complete.