Vertical? Obtuse? Straight or acute

Answer:
D. Acute
Step-by-step explanation:
This is an acute angle because the angle is less then 90 degrees.
<FOA is an Acute angle (D).
How I know...
Acute angles are angles are below 90 degrees (aka LESS then a right angle)
Hope this helped!
~Just a girl in love with Shawn Mendes