From the given situation above, we form a right triangle with legs equal to the height of the tree and the length of the shadow it casted. The hypotenuse is the length from the tip of the tree to the tip of the shadow.
The angle at which the ray of the sun hit the ground is that which has a tangent equal to 100 / 150 or 2/3. This angle is equal to 33.69. Thus, the answer is letter B. 34°.