Answer:
B. False, they could be vertical angles
Step-by-step explanation:
Supplementary just mean when two angles form 180° (a straight line).
So ∠F and ∠G must form a straight line, and ∠G and ∠H must form a a straight line.
I drew the image out below and as you can see, angle F and H forms a vertical angle. A vertical angles is when two lines cross, the opposite angles from each others are called vertical angles.