I got my passport when I was single. I then married and divorced after 7-8 months. Now I am applying for a visa where it asks for marital status as: singe/never married, divorced and so on. Do I need to choose the single/never married option or the divorced one? I am confused as my passport mentions SINGLE. Will it affect my visa decision?
Always, always, always tell the truth in your applications. If someone notices a discrepancy, you have the explanation: the passport was issued before the marriage and divorce.
As to whether this will affect the application, that depends on what kind of visa you are applying for, to which country, and many other details you have left out of your question. But there isn't a visa in the world where "lie on your application so it matches the out-of-date information from when your passport was issued" is the right thing to do.