Hydrochloric acid and sodium hydroxide are mixed together to form salt and water. during the reaction, the temperature of the solution increases. which of these best explains why this is considered to be a chemical change?

It's a chemical change because bonds are being broken and formed.

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.