下列说法表示“特回答贵公司某月某日函所叙述有关事项等”的是（ ）
A.I have the pleasure of stating, in answer to your inquiry of the 4th inst, that
B.In reply to your letter of the 5th of May, I have to inform you that (of)
C.I hasten to answer your inquiry of the l5th May, by stating that