Which of the following chemicals, when pure, will have different properties if it is synthesised in the lab.?

d. none of these. If you isolate a pure natural substance and then synthesize the same substance in the laboratory, upon comparison you will see that both samples will have exactly the same properties. This is because the two chemical entities are identical whether they are natural or synthetic. If the synthetic sample did not exhibit the same properties as the natural sample, then that means you didn't actually make what you were trying to make and you will have to go back and reevaluate your synthesis.