SAT Question c8d60e48: Lines, Angles, and Triangles answer and explanation with Desmos solution

Choice B is correct. Since $AB=AC$, the measures of their corresponding angles, $\angle ABC$ and $\angle ACB$, are equal. Since $\angle ABC$ has a measure of $67^{\circ }$, the measure of $\angle ACB$ is also $67^{\circ }$. Since the sum of the measures of the interior angles in a triangle is $180^{\circ }$, it follows that $67+67+x=180$, or $134+x=180$. Subtracting $134$ from both sides of this equation yields $x=46$.