Final answer:
A water-filled manometer must be 13.6 times taller than a mercury manometer to measure the same pressure, so for 300 mm Hg, it needs to be 4.08 m tall, but none of the provided options are correct.
Step-by-step explanation:
The question asks: How tall must a water-filled manometer be to measure blood pressure as high as 300 mm Hg? This is a Physics problem related to fluid statics and the measurement of pressure using a manometer. To answer this, we must consider the density of the fluids. Mercury is 13.6 times denser than water, meaning a water manometer must be 13.6 times taller than a mercury column to measure the same pressure. Therefore, to measure 300 mm Hg with water, we need a manometer of 300 mm Hg * 13.6, which equals 4080 mm, or 4.08 meters tall. However, the options provided do not include this value, indicating a possible mistake in the question as the given choices are not feasible for a water manometer.