Complete the sentence with the correct form of the verb in brackets: "The union has ____ (strike) a deal with the management at last."

Explication

After has, the verb needs its past participle, and strike follows the two-form pattern: struck serves as both the past simple and the participle, so the union has struck a deal is correct. Striked does not exist in standard English, and the base form strike cannot follow has on its own.