The tension in the string can be calculated using the equation T = (W - F) / sin(θ), where T is the tension, W is the weight of the rod, F is the weight of the load, and θ is the angle formed by the string. In this case, the weight of the rod is 10 N, the weight of the load is 20 N, and the angle is 37°. Plugging in these values, we get T = (10 - 20) / sin(37°) = -10 / 0.6018 ≈ -16.6 N. Since tension cannot be negative, we take the absolute value and round it to one decimal place, giving us 16.6 N. Therefore, the correct answer is B. 41.7 N.