Theory VS Logic

The Primary 4 kid I tutored; presented me with a Science question set by her teacher from a top convent primary school in Singapore. She was asking me to check if she had answered correctly.

I'm sure we all know teachers usually set questions within the textbook's context expecially for the primary science subject. And this question tested on the student's knowledge both on the basic theory of expansion for matters when heated and the conductors of heat.

I did come across some questions bordering on impracticality for the sake of testing one's knowledge on a basic theory before. But this question had me thinking if the teacher while setting this question had a bit of mental block then.

The question and my student's attempted answers. Make your own judgement.

Mr. Gecko carried out the experiment above. He wrapped half of a copper rod and half of a glass rod with a piece of white paper as shown. He heated the middle of the paper above a candle for 15 mins.

A) Describe what he would observe on the paper after 15 mins.
The paper will burn.

B) Explain your answer.
Paper gets burnt easily.

C) Describe what Mr. Gecko would observe on the paper if he replaced the glass rod with an iron rod
The paper will be burnt.

After going through my student's answer, I found it difficult for me to explain to her why she had answered wrongly and why she is not to give such common sense answers especially for a 5 marks science question for her end of year exams.

Theory versus common logic. For a Primary 4 science question, which wins?