The correct option is B 30 cm
Rain
gauge can accurately measure the rainfall without any loss due to evaporation.
It is an instrument used for determining the depth of precipitation that occurs
over a unit area. Thus, it measures rainfall. One liter of rainfall per meter
squared is equivalent to one millimeter of measured precipitation. A funneled
aperture of 150-170 cm is found in standard rain gauges. They are designed as a
simple passive collector. A graduated measuring glass is used for determining
the amount of precipitation. For the measurement of rainfall, the rain gauze should
be placed 30 cm above the ground to
prevent the splashing of rainwater.