At point A, three rays AB,AC, and AD are drawn such that AB and AD are opposite rays and AC lies in between them. A student observes that ∠BAC and ∠CAD are equal and concludes that they are vertically opposite angles.
a. (i) Explain why the student's conclusion is incorrect.
b. (ii) Correctly classify the relationship between ∠BAC and ∠CAD with justification.
c. (iii) If ∠BAC=68∘, find ∠CAD and ∠BAD.