Answer:
(C)
Explanation:
It is given that The steepest side of the model, AB, measures 4 inches, thus
From ΔABC, using the trigonometry, we have

Substituting the given value, we have
⇒

⇒

⇒

Now, from ΔACD, we have

⇒

⇒

Therefore, the length of AD will be

thus, option C is correct.