Can you show the full question?
Answer:
Gabriela Mistral works as a humanitarian for
days.
Step-by-step explanation:
Gabriela Mistral was a poet, diplomat, teacher and humanitarian such that each week she worked a certain amount of days as a poet diplomat teacher and humanitarian.
Ratio is 
Let
denotes total number of days Gabriela Mistral work.
As she works 12 days as a teacher,

Total number of days 
So,
she works as a humanitarian for
days.
Answer:
Option B, random sample
That should be the answer