The correct answer is B.
Nǐ bú qù pǎobù ma?
Li Hua：你不 去 跑步 吗？
Aren’t you going running?
Bú qù.
Sam：不 去。
No.
Wèishénme?
Li Hua：为什么？
Why?
Yīnwèi tiānqì bùhǎo, suǒyǐ wǒ bùxiǎng qù pǎobù.
Sam：因为 天气 不好，所以 我 不想 去 跑步。
I’m not going running because of the bad weather.
Explanation:
According to the translation, we can see that Sam won’t go running because of the bad weather. So what we need here is a cause-effect conjunction. 因为 (Yīnwèi) means “because,” or “since” and 所以 (suǒyǐ) is “so,” or “therefore.” In Chinese they are often used together to describe cause and effect. For example,
虽然 (suīrán) and 但是 (dànshì) also work as a pair, but these two put together are a transitional conjunction. Its meaning is similar to “although.” In Chinese, 虽然 (suīrán) means “although,” or “though” and 但是 (dànshì) means “but” or “however.” For example, 虽然你的成绩很好，但是 你不能骄傲。(Suīrán nǐ de chéngji hěn hǎo, dànshì nǐ bù néng jiāo’ào. Although you got a high score, you can’t be proud.) In English, there is no “but” before the sentence “you can’t be proud,” but 但是 (dànshì) must be used in the Chinese sentence.
不但 (búdàn) is similar to the English conjunction “not only,” and 而且 (érqiě) is the same as “but also.” They are used together in Chinese to express a climactic relation of meaning. For example, 她不但长得漂亮，而且学习好。(Tā búdàn zhǎng dé piàoliang, érqiě xuéxí hǎo. She not only looks beautiful, but also does great in her studies.)
Examples:
Yīnwèi tā bù shūfu, suǒyǐ tā jīntiān méiyǒu shàngbān.
1. 因为 她 不 舒服，所以 她 今天 没有 上班。
She didn’t go to work today because she is ill.
Suīrán shàngbān hěn lèi, dànshì tā hěn gāoxìng.
2. 虽然 上班 很 累， 但是 他 很 高兴。
Although going to work is very tiring, he is happy.
Píngguǒ búdàn hǎochī, érqiě hěn yǒu yíngyǎng.
3. 苹果 不但 好吃，而且 很 有 营养。
Apples are not only delicious, but also nutritious.
HSK Test
General Chinese (Beginner Level)
General Chinese (Intermediate Level)