Furrows of 150 m long and 2 m apart, have longitudinal slope of 0.5 percent are initially irrigated by non-erosive stream for 100 minutes. The stream size is reduced to 50% and continued for another 40 minutes. Determine the average depth of irrigation.

• A. 50.34 mm
• B. 43.56 mm
• C. 47.58 mm
• D. 43.84 mm