How should your knees be positioned in good standing posture?
a. slightly bent
b. as rigid as possible
c. slightly abducted
d. slightly adducted

Well if dealing with an posture you would either make a slightly bent knee to get in an current position where you are suppose to be so I would say to have your knee slightly bent for your position :) hoped I helped  

They giveaway sto the public

Think it's rice because in many countries rice is the main food so it can be traditionally served all at once.