Explanation:
In the given question, the study was performed to analyse the effect of eating dark chocolate on the person with hypertension or increased blood pressure.
a) The biasness in the experiment could be that the funding for the study has been provided with a Private Company which mainly aims at selling their product.
b) The research is reasonable as it has been proved that eating a small amount of Dark chocolate can help cardiovascular disease like hypertension or increased blood pressure.