Water of density 1000 kg/m³ flows through a horizontal pipe. The left-hand limb of a U-tube manometer is connected to a static pressure tapping at a given cross-section in the pipe and the right-hand limb is open to the atmosphere. If the difference in the heights of the two limbs of the manometer is 20 cm, the pressure difference between the pipe and the atmosphere is closest to:
a) 1.96 kPa
b) 1.96 Pa
c) 196 kPa
d) 19.6 kPa