Consider the following product structure.

B$(1)$

D $(2)$

E $(1)$

If the demand for product A is $5$ units, how many units of component F will be needed?

$$ A$.10$

$$ B$.5$

$.20$

$$ D$.3$

O E$.$

$15$

C $(1)$

F $(2)$

$$

D $(1)$

F $(1)$