"How is the child's answer?"
Translation:Câu trả lời của đứa trẻ như thế nào?
I'm confused by your question. Are you asking about the English or the Vietnamese sentence? (I feel the Vietnamese sentence is just a direct translation from the English.) Either way, the "how is" sentence is a broad question type that allows the speaker the freedom to answer as he/she wishes.
Now, when I throw in the towel and try:
"Đáp án của đứa trẻ như thế nào" (because DL seems to be marking all the 'làm sao' constructions wrong, contrary to what the course notes say) it now says "GOTCHA AGAIN!! WRONG AGAIN!!", the answer should be:
Đáp án của đứa trẻ thì thế nào?
Where'd the 'thì thế nào' come from? Of course, somehow, someway, we are expected to know this.
như thế nào = how was it
làm sao = what actions were performed [to lead to this conclusion]
eg: "how did you do?" vs "how did you do this?"
One calls for a description of conditions and the other asks for actions taken. You can see that the English sentence given they asks more what the child's answer was like rather than the steps he took to make words come out of his mouth resulting in a reply.
They give us frustrating sentences for the same reason that they gave us words in the first lesson that are practically tongue twisters for non-Vietnamese (cá, ca, gà). Examples that frustrate the most best illustrate the different concepts being taught. Would you prefer that learners developed a false sense of competence and encountered these frustrating yet common tricky cases in the wild?