Concept:Shares that are authorized but not yet issued remain unissued until the company offers them to investors.Explanation:The company has an authorized capital of 100 million shares at N1 per share.Out of these, only 50 million shares have been issued and fully paid-up.The other 50 million shares have not been offered or sold to the public.Therefore, these remaining shares are simply not yet issued.Answer:A. Not yet been issued.