Explanation:

- Suraj waved to a train that had already passed by, which indicates a past action.

- The verb that best fits is in the past tense, as the rest of the passage is in the past tense.

- Option 1: liked – This is the past tense form of "like," which fits well with the narrative of Suraj's past actions.

- Option 2: likes – Present tense, not suitable here as the passage is in past tense.

- Option 3: is liking – Present continuous tense, does not match the past narrative.

- Option 4: was liking – Past continuous tense, generally used for an action that was ongoing, but this sentence requires the simple past.

Thus, the correct answer is Option 1: liked. .