The correct option is B certificate of incorporation
On receipt of the certificate of incorporation, the public company has to complete certain other legal formalities such as a statutory meeting (within 6 months), statutory report, etc. On completion of the said formalities and on filing of the statutory report with the ROC the ROC issues the certification of commencement of business to the company. Thereafter, the Public Company can start the business operations. The Private Company can start its business immediately on incorporation.