If sin(A) = 1/2, what is "A"?
Recall that there are some special angles for which it is easy to recall their trigonometric forms and values.
Those angles are called "special angles"
The one in particular that renders sin(A) = 1/2 is when A is 30 degrees, wich is equivalent to the following in radians:
30 * pi / 180 = pi/6
which is answer C in your list.
