20.
Your Answer is
Correct Answer is F
Explanation
According to the meaning of the sentence, made festive with flowers and pink balloons modifies the boat, item F is correct.
G item: for as a conjunction means "because", there is no causal relationship before and after.
Item H: which guides the attributive clause as the subject or object in the clause.
Item J: making it...is not a complete sentence, and a period cannot be used before it.