Q. The maximum value of θ until which the approximation sinθ ≈ θ holds to within 10%
error is
(A) 10 degree
(B) 18 degree
(C) 50 degree
(D) 90 degree

according to me answer should be B i.e. 18 degree but my teacher gave answer of this C i.e. 50 degree but this is unacceptable for me as in this approximation error would be more than 13%.