Can anybody help me with this problem regarding Line Integrals? Compute ∫F*dr, given the counterclockwise unit circle C : cos((pi)t), sin((pi)t), t∈[0,2] and the vector field F(x, y) = (y²,-x²)

The water company charges a residential customer $41 for the first 3,000 gallons of water used and $1 for every 200 gallons used over 3000 gallons. if the water bill was $58 how many gallons of water were usedanswersa 3400 gallonsb 6000 gallonsc 6400 gallons d 7000 gallons