Which of the following is a step in constructing a circle inscribed in a triangle?

Which of the following is a step in constructing a circle inscribed in a triangle?
a. Use a compass to locate the intersection of the midpoint of each side.
b. Use the perpendicular bisectors to find the center of the circle.
c. Use a compass to locate the intersection of the altitude of each side.
d. Use the angle bisectors to find the center of the circle.