What is the correct SI base unit for the gradient of this work-time graph?
kg m s−2\text{kg m s}^{-2}kg m s−2
kg m2s−2\text{kg m}^2 \text{s}^{-2}kg m2s−2
kg m2s−3\text{kg m}^2 \text{s}^{-3}kg m2s−3
kg m2s−1\text{kg m}^2 \text{s}^{-1}kg m2s−1
