The correct option is B Plot B
The plot with maximum area has to be used by the farmer.
Area of Plot A = Length × Width
= 50×45
= 2250 square feet
Area of Plot B = Length × Width
= 60×40
= 2400 square feet
Area of Plot C = Length × Width
= 70×30
= 2100 square feet
Area of Plot B > Area of Plot A > Area of Plot C
Hence, Plot B has the maximum area.