Answer:
b. decrease the supply of the service
lead to higher prices charged for the services.
Explanation:
A license requirement impedes the entry of potential suppliers to the market, either because some suppliers cannot pay for the license, do not wish to do so, or do not meet all the criteria. This causes the number of suppliers to be less than it potentially could be, while demand stays the same.
If demand stays the same, but supply is reduced, then, the equilibrum price will be higher, because consumers cannot obtain as much of the good as they wish, and therefore, have to pay more for it.