Answer :
Answer:
(D) [tex]\angle CAB[/tex].
Step-by-step explanation:
The diagram is attached below:
Theorem: An exterior angle of a triangle is equal to the sum of the opposite interior angles.
The exterior angle is the angle formed by the third side and a straight line which forms a supplementary angle with the third interior angle.
In the diagram:
[tex]\angle ABF$ and \angle AFB[/tex] are opposite interior angles.
The third angle is [tex]\angle BAF[/tex]
The angle which forms a supplementary angle with [tex]\angle BAF[/tex] is [tex]\angle CAB[/tex].
Therefore, the exterior angle of triangle ABF is [tex]\angle CAB[/tex].
