Having spent $5$ years developing a new medicine, a pharmaceutical company finally started testing it$.$ To test the medicine, they used a sample of $500$ patients. The company found that while $350$ patients benefited from the medicine, the remaining $150$ did not see any improvements in their condition after taking the medicine. The company concluded that their medicine was unconditionally effective at treating the condition and began manufacturing this medicine. It can be said that the company made their decision relying on:

fundamental attribution error

availability heuristic

confirmation bias

ambiguity aversion