Explanation:
The correct answer is 'has been following' because the sentence implies an ongoing action that started in the past and is still happening in the present. Here is a detailed explanation:

Present Perfect Continuous Tense:
- The sentence "A strange man has been following us for hours" uses the present perfect continuous tense.
- This tense is used to describe an action that started in the past, has continued up to the present, and may continue into the future.
- In this case, the strange man started following the speaker and has continued to do so for hours without stopping.

Continuous Action:
- The use of "has been following" indicates that the action of following is ongoing.
- The strange man did not just follow the speaker once, but has been following them continuously for a period of time.

Duration of Time:
- The phrase "for hours" indicates the duration of time that the strange man has been following the speaker.
- This emphasizes that the action has been happening for an extended period without interruption.

Implication of Creepiness:
- The use of the word "strange" to describe the man adds a sense of creepiness or unease to the situation.
- The continuous nature of the following enhances the feeling of being watched or followed.
In conclusion, the present perfect continuous tense "has been following" is the correct choice in this sentence because it conveys the ongoing and continuous action of the strange man following the speaker for hours.