Help Please! and Thank you!!

Answer:
Option D. [tex]50^{\circ}[/tex]
Step-by-step explanation:
[tex]\angle A + \angle B + \angle C = 180[/tex] (angles of a triangle sum to [tex]180^{\circ}[/tex])
[tex]\angle A + 100 + 30 = 180[/tex]
[tex]\angle A = 50^{\circ}[/tex]
Hope this helps :)