\angle{BAC} is said to be “laceable” if distinct points X_1,X_2,\dots,X_{2n} can be found so that
- X_{2k-1} is on AC for each value of k,
- X_{2k} is on AB for each value of k, and
- X_1=X_1X_2=X_2X_3=\cdots=X_{2n−1}X_{2n}=X_{2n}A.
For example, the angle 20^\circ is laceable, as shown. The number of laceable acute angles, whose sizes in degrees are integers, is
Answer Choices
A. 3
B. 4
C. 5
D. 6
E. 7