单项选择题

Questions 150-152 refer to the following letter.
Dear Heimer,
I am pleased (150) that your order on March 3 is now ready for dispatch
When (151) your order, you emphasized the importance of prompt delivery and I am glad to say that by making a special effort I have been able to send them a few days (152) than agreed upon.
I now wait for your shipping instructions. On receiving them, I will send you our invoice. Detailed terms are available upon request. Thanks.

A. early
B. earlier
C. earliest
D. earliness