Answer:
The sentences that contain gerunds are:
3. Thinking is hard when you are under pressure.
4. Junior got a timeout for running in the halls.
Explanation:
A gerund is formed by adding -ing to the base form of a verb. For that reason, it looks exactly like a present participle. Examples: swimming, singing, eating, thinking, etc.
However, in a sentence, gerunds function just like nouns, which means they play the same roles nouns do in the sentence such as subject, direct or indirect object, and complement.
With that in mind, we can eliminate the first two options, which contain a present participle functioning as an adjective and as part of a progressive tense. The last two options contain gerunds functioning as nouns. They are the ones we should pick.