Question tags turn a statement into a question. They are often used for checking information that we think we know is true. Usually if the main clause is positive, the question tag is negative, and if the main clause is negative, the question tag is positive. For example: It's cold (positive), isn't it (negative)?
From the sentence, ''It seems that the children are not paying attention, (Negative) are they (positive)? Option A is the correct answer