The steps shown can be used to prove that the medians of a triangle meet at a point. what is the final step to complete the proof?

the proof:
1. define segments bd and ce as medians of trianngle abc

2. write a linear equation for line bd and line ce

3. use a system of linear equations to solve for the coordinates of intersection point g

4. write the equation of line ag

5. write an expression for the midpoint of lije segment bc, pount f

6. ?

choice of answers:
a) write a linear equation for each side of the triangle

b) write an expression for the midpoint of line segment ac and line segment bc

c) show that line segment a. f is congruent to line segment bd and like segment ce

d) show that line segment a. f is the median of line segment bc