21. Which of the following is the BEST reply to theletter?

[20~21] Read the following and answer the questions.

We have recently concluded a contract for the supply of raw cotton from New Orleans to Manchester over the next twelve months and should be glad if you would find us a suitable ship, about five thousand tons. The question of speed is important as the ship we need must be able to make six return voyages in the time, allowing for six days at each turn-round.

• ①
  Flights are made daily, except on Sundays, andyour parcel should reach its destination in notmore than three days.
• ②
  We should be glad if you would handle theconsignment for us, but first send us details ofthe cost and of any formalities to be observed.
• ❸
  We are glad to inform you that we have found aship which we think would serve you very well.
• ④
  Although we would have preferred a larger ship,this will suit our needs and we confirm ourtelegram as follows.