unsure with these two. thank you!

Contribution margin ratio is computed by O A. dividing sales revenue by contribution margin. O B. dividing contribution margin by sales revenue. O c. dividing contribution margin by operating income. OD. dividing operating income by contribution margin. With respect to total fixed costs, which of the following statements is true? O A. They will remain the same as production levels change within the relevant range. OB. They will increase as production decreases within the relevant range. O c. They will decrease as production increases within the relevant range. OD. They will decrease as production decreases within the relevant range