Since the question is telling you that both the triangles are essentially the same, you just have to look to see which letter of triangle ABC is in the same general place as triangle DEF.
In this case angle B is in the same general spot as angle E, so therefore B is your answer.
<span>Critical points are where the derivative is 0, i.e. where it crosses the x - axis
The Critical points lies where the derivative is 0, while it crosses the x-axis, SO, in this case the choice 3 looks like best answer for this. </span>
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