Select the correct active form of the given sentence.

Three online games of chess were won by Rahul in a row.

Rahul won three online games of chess in a row.

The correct active form of the given sentence is Rahul won three online games of chess in a row.

The sentence "Three online games of chess were won by Rahul in a row" is in the passive voice, with the subject "three online games of chess" and the verb "were won." The passive voice is formed by putting the subject of the active sentence after the verb "to be" and the past participle of the main verb. In this case, the subject of the active sentence is "Rahul" and the main verb is "win." The past participle of "win" is "won." So, the passive form of the sentence is Three online games of chess were won by Rahul in a row.

The active form of the sentence puts the subject of the sentence, "Rahul," before the verb "win." The verb "win" is followed by the direct object, "three online games of chess," and the prepositional phrase "in a row."

The other options are incorrect because:

• Rahul has won three online games of chess in a row. is in the present perfect tense, while the original sentence is in the simple past tense.
• Rahul was winning three online games of chess in a row. is in the past progressive tense, while the original sentence implies that the winning has already happened.
• Rahul had won three online games of chess in a row. is in the past perfect tense, while the original sentence is in the simple past tense.