Which of the following compounds can yield only one monochlorinated product upon free radical chlorination?

Which of the following compound can give only one monochlorinated product upon free radical chlorination?

Which of the following compounds yields only one product on monobromination ?

Which of the following compounds yields only one product on monobromination ?

Which of the following isomeric heptanes can yield seven differentt monochlorinated products upon free radical chlorination?