please answer

Quantity Private ValuePrivate CostExternal Cost (Units) (Dollars) (Dollars) (Dollars) 1 46 21 6 2 44 24 6 3 42 27 6 4 40 30 6 38 33 6 6 36 36 6 34 39 6 Refer to Table 10-4. The table represents a market in which Oa. there is no externality. Ob. there is a negative externality. Oc. The answer cannot be determined from inspection of the table. Od. there is a positive externality