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In the water supply system of a certain office building, the booster pump draws water from a reservoir; the total length of its suction pipe and discharge pipe is 50.00 m. The height from the lowest level of the reservoir to the most unfavorable point for water distribution is 35 m. The head loss in the pipeline from the pump’s suction pipe to the most unfavorable point for water distribution is 4.15 m H2O (1 m H2O = 9.80665 kPa), while the head loss due to the water meter is 1.65 m H2O. The required outlet head at the most unfavorable point for water distribution is 20 kPa, and the pressure provided by the outdoor water supply network is 180 kPa. Therefore, the minimum head that the pump must generate is ( ) kPa. A. 411.5 B.428.0 C. 248.0 D.561.5 Answer: A is the correct answer. According to Equation (2.5) in Section 2.2 of \"Building Water Supply and Drainage Engineering\" (4th edition), which deals with the calculation of head when a pump is connected indirectly to the external network, the head of the pump should be calculated as Hb=H1+H2+H3. In this problem, H1 = 35.00 m H2O, H2 = 4.15 m H2O, and H4 = 2 m H2O; therefore, the calculated minimum value of Hb is 41.15 m H2O, which corresponds to 411.5 kPa. Option B includes the head loss of the water meter ； Option C is incorrect; it calculates based on a direct connection between the water pump and the external network ； Option D mistakenly takes the total length of the suction pipe and the pressure pipe as H1.