Which of the following compounds would you expect to be strongest carbon acid ?

Which one of the following acids would you expect to be the strongest ?

Which one of the following acids would you expect to be the strongest?

Which one of the following acids would you expect to be the strongest?

Which of the following compounds would you expect to have a dipole moment ?

Which of the following compounds would you expect to have a dipole moment ?

Which of the following compounds would you expect to be the major product when 2-bromo-2methylbutane is refluxed with KOH/ethanol?