Which of the following would not be a clear indication of a chemical change

I believe the answer is "After adding two substances together a new order is detected" because nearly all of the other answers suggest a chemical change has taken place. The reason I say "almost" is because answer two and four results in bubbles forming so the answer cannot be both. The only one to not clearly show a chemical change has occurred is the last answer.

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2

idk what is it? is this a question that you know the answer or u dont