Answer: using taxes to help failing banks
Step-by-step explanation:
Adam Smith believed that competition was good for the economy because it would lead to only the most efficient companies surviving as they outlast those who were not efficient and had to close up because they couldn't compete with the efficient ones.
Failing banks would fall under companies that were not efficient enough and so to Adam Smith, should not survive. Aiding these banks therefore so that they would survive, would be opposed by Adam Smith because it would mean that inefficiency was being rewarded and resources of the country were not be distributed efficiently.