Fill in the blanks with the most appropriate option:-

If I ________ a child, I would play in the rain.

were

The most appropriate option to fill in the blanks is were.

The sentence "If I were a child, I would play in the rain" is in the subjunctive mood, which is used to talk about hypothetical situations. The other options are not as appropriate.

• Was is the past tense of the verb "to be". This does not make sense in the context of the sentence, as the speaker is not talking about a real situation that happened in the past, but a hypothetical situation.
• Am is the present tense of the verb "to be". This does not make sense in the context of the sentence, as the speaker is not talking about their current state of being.
• Will is the future tense of the verb "to be". This does not make sense in the context of the sentence, as the speaker is not talking about a future event that is certain to happen, but a hypothetical event.