calculate the amountnof heat needed to melt 81.9 g of solid acidic and brinf it to a temperature of 31.5 c

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.

B? i feel like this is a trick  

Answerspecies;

The answer is a. stable, hope i ya