Concept:A prospectus is a formal public invitation to invest in a company's securities.Explanation:A company issues a prospectus to invite the public to apply for its shares or debentures.This means the public is asked to subscribe to the company's shares.It is not an invitation to purchase the company's products.It is also not an invitation to attend board meetings.Therefore, the correct choice is clear from the purpose of a prospectus.Answer:A. subscribe to the company's shares