SKorean stock market tumbles amid trade wars

What is the primary function of the word 'But' in a sentence?

• To introduce a new topic

• To add similar ideas

• To contrast different ideas

• To emphasize a point

Which of the following sentences correctly uses 'But' to show contrast?

• They are friends, but they enjoy spending time together.

• He is tall, but he is a basketball player.

• She likes apples, but also likes oranges.

• I wanted to go for a walk, but it was raining.