Please it's due today I need help to solve this

Answer:
A
Step-by-step explanation:
The angle between 30⁰ and S⁰ is 60⁰ because it adds up with 30⁰ to give 90⁰.
Then 60⁰ + S⁰ = 180⁰. Evaluate this and it gives you S⁰ = 120⁰.