Answer:
B) linear function with a positive rate of change
Step-by-step explanation:
Each increase by 1 m^2 in area produces the same 0.2 kW increase in power, so the relationship between area and power is linear. Since they both go up (or both go down), the "rate of change" is positive. (If it were negative, one would go down when the other went up.)
The best description is that of B.
