Answer: c. Patients with diabetes now have a steady, inexpensive supply of insulin available.
Step-by-step explanation:
Insulin used to be acquired from slaughtered cows and pigs which meant that supply was low as there are only so many animals that you can kill at a time that would be accessible to insulin makers. With low supply comes higher prices as per demand and supply rules.
With humans now being able to produce insulin for themselves by use of a bacterium, it means that insulin can be produced in much higher quantities which will increase supply and decrease prices.