根据短文，从A、B、C、D四个选项中选择正确答案填空。

    It's December 28th. New Year's Day is 1. Ma Li is in a 2 shop. She wants to buy a blouse 3 her mother. She is happy because she 4 a blue blouse. It looks pretty. She thinks it 5 her mother's trousers well, so she asks the shopkeeper what the 6 is. “198 yuan,” says the shopkeeper. Ma Li is surprised (吃惊的), “Too 7! What's it made of?” The shopkeeper tells her the blouse is made of silk. “Good things always 8 much,” he says.

  “But I have only 190 yuan. Can it be cheaper (更便宜)? I buy it for my mother. ”

  “9. 198 yuan is the last price. But I will lend you 8 yuan.”

  “10? We don’t know each other.”

  “Because I love my mother, too,” says the shopkeeper with a smile (微笑).

在孟德尔进行的一对相对性状的实验中，具有1：1比例的是    (  )