The correct option is B fight
Let’s examine the sentence: “Organised labour has fight for and won protection and benefits for its workers.” The sentence talks about actions that have recently completed in the present and attained their results. So, it is in present perfect tense. The present perfect is made using the auxiliary verb 'have/ has' plus the 'past participle' of the main verb. So, past participle of the verb will be used. The sentence already uses the past participle of the verb ‘win’ and, so to keep the verb agreement intact, the verb ‘fight’ should also be used in its past participle form. Hence, ‘fought’ should be used here. Hence, the word or phrase that must be changed for the sentence to be correct is indicated by Option B. Option B is the correct answer.