The correct option is B he
A relative pronoun functions as a pronoun as well as a conjunction. As a pronoun, it refers to a noun which is common between two sentences and as a conjunction, it combines those sentences as one. The antecedent is the noun that the relative pronoun refers to, or relates to the rest of the sentence. In some cases, when a sentence is spoken in general sense, the antecedent can be omitted and is only implied in the sentence. From the given options, 'he' is the antecedent, when placed in "He who wins the battle may lose the war', here 'who' refers to 'he', hence option A is correct. 'Who' is the relative pronoun, as it refers to the antecedent and not the antecedent itself, hence option B is incorrect. 'Wins' is a verb that performs the action 'to be victorious', it isn't the antecedent as 'who' does not refer to it. Hence option C is incorrect. 'Lose' is also a verb that means 'to be unsuccessful in something', hence option D is incorrect.