seth is using the figure shown below to prove pythagorean theorem using triangle similarity:

in the given triangle abc, angle a is 90o and segment ad is perpendicular to segment bc.

which of these could be a step to prove that bc2 = ab2 + ac2?
a. by the cross product property, ab^2 = bc multiplied by bd
b. by the cross product property, ac^2 = bc multiplied by bd
c. by the cross product property, ac^2 = bc multiplied by ad
d. by the cross product property, ab^2 = bc multiplied by ad