A maize crop is growing well in a field where the water potential of the soil is $-40\ \text{kPa}$. What is the most likely water potential of the cell sap in the root hair cell?
- A$-60\ \text{kPa}$
- B$-40\ \text{kPa}$
- C$-20\ \text{kPa}$
- D$0\ \text{kPa}$