The conclusive evidence of registration of a firm is the certificate of registration of firms. Let's understand why this is the correct answer in detail.

Certificate of Registration of Firms:
- The certificate of registration of firms is a legal document issued by the Registrar of Firms, which is the conclusive evidence of the registration of a firm.
- It serves as proof that the firm has been registered under the Indian Partnership Act, 1932.
- The certificate contains important information about the firm, such as its name, address, date of registration, and the names of the partners.

Certified Copy of Register of Firm:
- While the certified copy of the register of firm is an important document, it is not the conclusive evidence of registration.
- The register of firm is maintained by the Registrar of Firms and contains details such as the name of the firm, its partners, and their addresses.
- A certified copy of the register can be obtained for reference purposes, but it does not serve as proof of registration.

Register of Central Government:
- The register of central government is not directly related to the registration of a firm.
- The central government maintains various registers for different purposes, but they do not provide conclusive evidence of a firm's registration.

None of These:
- This option is incorrect because the certificate of registration of firms is indeed the conclusive evidence of registration.

In conclusion, the certificate of registration of firms is the conclusive evidence of a firm's registration under the Indian Partnership Act, 1932. It is a legal document issued by the Registrar of Firms and contains vital information about the firm. While other documents such as the certified copy of the register of firm and the register of central government are important, they do not serve as conclusive evidence of registration.