Query about Question 7 from "(I'm Overwhelmed) Geometry Progress Quiz #1" [7679]

https://www.gregmat.com/quizzes/quiz/im-overwhelmed-geometry-progress-quiz-1 (Question 7)


how do we know x was an angle here? I picked D

Though Qb can tell us x is an angle, specifying could help @Leaderboard what do you think?

Normally it should be obvious, but I can see why it isn’t here. That’s fixed.