Americans Are Always Connected Today, Talking on the Phone at Home

Americans are always connected today, talking on the phone at home, while driving down the road and while shopping for groceries. But that wasn't always the case. In fact, it wasn't that long ago people had to go through an operator in order to get connected with the person they were trying to reach. How do cell phones impact the labor market for telephone operators?

A) Decreased telephone operators' value of marginal product
B) Increased the demand for telephone operators
C) Increased the supply for telephone operators
D) Decreased the marginal productivity of telephone operators