There're only 800 people in Fairfield, and most of them do the same thing at the same time

every' week day. Every morning, Monday through Friday, when the big clock strikes seven, old Bruce Hunt walks past the Farmers' Bookshop. He's on his way to work at the bus-station. And when Bruce walks past the book shop, Robert Brown opens his shop next door and waves to Bruce. When Robert waves to Bruce, you can set your watch and you know it's seven.

If you miss Bruce and Robert, you can set your watch when Miss Mary Smith opens the door of the post office. You know it's seven fifty-five. She has five minutes to get ready for work—to put away her raincoat

and take off her hat and coat. Rain or shine, Miss Mary Smith brings raincoat. "You never can tell what the weather will be like when it's time to go home," she always says.

One after another the shops along Main Street open for the day. The clothes shop and the fruit shop get open for business. When Mr. King opens the bookshop, the clock above the shop strides nine.

But every weekday, people go to bed early in Fairfield. The streets are quiet, and the houses are dark when the big clock over the Farmers' Bookshop strikes tell o'clock. The small town is getting ready for tomorrow.

The post office starts its business at ______ every weekday.

A．7:00

B．7:55

C．0.333333

D．0.375