The correct answer is (a). Section 45-A of the Indian Evidence Act makes relevant the opinion of the certifying authority which issued the electronic signature.
Section 45-A states that the opinion of the certifying authority which issued the electronic signature shall be relevant in proving the validity of the electronic signature. The certifying authority is a person who has been authorized by the Central Government to issue electronic signatures.
The opinion of the certifying authority is relevant because it is an expert opinion on the validity of the electronic signature. The certifying authority has the expertise to assess the validity of an electronic signature, and its opinion is therefore given weight by the court.
The other options are incorrect because they do not make relevant the opinion of the certifying authority which issued the electronic signature. Section 47-A deals with the admissibility of electronic evidence, Section 53-A deals with the presumption as to the genuineness of electronic records, and Section 73-A deals with the admissibility of electronic evidence in certain cases.