A, according to the definition of capacitance C=? S4πkd, keep S unchanged, increase D, and the capacitance C decreases. Then, according to U=QC, we know that U increases, so θ increases. So, A is right and B is wrong.
C, keeping d constant, increasing S, increasing capacitance, and then according to U=QC, we know that U decreases, so θ decreases. So, the CD is wrong.
So choose one