Topic: Conditional Sentence,

Best Answer Explained in Below-:

The sentence in the question uses a conditional structure known as the subjunctive mood, which is often employed to express hypothetical situations that are contrary to fact. In the given example, "If I – a bird, I would have flown in the sky," and "If I-millionaire, I would have removed poverty," the speaker is imagining scenarios that cannot actually occur.

In English, the correct verb form for such hypothetical statements is "were." This is because we frequently use "were" instead of "was" in these subjunctive constructions, especially with the pronoun "I." Thus, the correct phrasing would be "If I *were* a bird" and "If I *were* a millionaire." This usage emphasizes the unrealistic nature of the condition, highlighting that the speaker is discussing an imaginary situation rather than stating a fact.

The other options — "become," "was," and "hads" — do not fit grammatically or contextually in this structure. "Become" is not used in this hypothetical form, "was" does not correctly employ the subjunctive mood, and "hads" is not a proper verb form. Therefore, the correct choice, "were," effectively conveys the intended meaning of these hypothetical scenarios.