Cathode ray that was the man we discoverd it hope tis helped
I believe the answer is B. <span>Contour farming
</span>In <span>Contour farming , we put the plant on perpendicular method, and </span><span>tilling sloped the land along lines of consistent elevation.
</span>By Doing this, we will ensure that every part of the soil will receive proper amount of water from the rainfall, hence prevent the chance of soil loss from surface erosion.
➡ 150hrs.
➡ Time = distance × speed
➡ Time = 15*10
➡ Time = 150hrs ans.