A container has a vertical tube, whose inner radius is 12.00 mm, connected to it at its side. An unknown liquid reaches level A in the container and level B in the tube-level A being 5.0 cm higher than level B. The liquid supports a 20.0 cm high column of oil, between levels B and C, whose density is 320 kg/m^3. The gauge pressure at level B is closest to:
a) 310 Pa
b) 940 Pa
c) 630 Pa
d) 470 Pa
e) 790 Pa